diff --git a/tools/setup/generate_integration_bots_avatars.py b/tools/setup/generate_integration_bots_avatars.py
index 39d6fb6af5..9f1600e6c1 100755
--- a/tools/setup/generate_integration_bots_avatars.py
+++ b/tools/setup/generate_integration_bots_avatars.py
@@ -21,7 +21,7 @@ from PIL import Image
 
 from zerver.lib.integrations import INTEGRATIONS
 from zerver.lib.storage import static_path
-from zerver.lib.upload.base import DEFAULT_AVATAR_SIZE, resize_avatar
+from zerver.lib.thumbnail import DEFAULT_AVATAR_SIZE, resize_avatar
 
 
 def create_square_image(png: bytes) -> bytes:
diff --git a/zerver/data_import/slack.py b/zerver/data_import/slack.py
index b6545f8a56..ab9d314745 100644
--- a/zerver/data_import/slack.py
+++ b/zerver/data_import/slack.py
@@ -47,7 +47,8 @@ from zerver.data_import.slack_message_conversion import (
 from zerver.lib.emoji import codepoint_to_name
 from zerver.lib.export import MESSAGE_BATCH_CHUNK_SIZE
 from zerver.lib.storage import static_path
-from zerver.lib.upload.base import resize_logo, sanitize_name
+from zerver.lib.thumbnail import resize_logo
+from zerver.lib.upload.base import sanitize_name
 from zerver.models import (
     CustomProfileField,
     CustomProfileFieldValue,
diff --git a/zerver/lib/avatar.py b/zerver/lib/avatar.py
index d4a50e8539..4e7882253b 100644
--- a/zerver/lib/avatar.py
+++ b/zerver/lib/avatar.py
@@ -9,8 +9,8 @@ from zerver.lib.avatar_hash import (
     user_avatar_content_hash,
     user_avatar_path_from_ids,
 )
+from zerver.lib.thumbnail import MEDIUM_AVATAR_SIZE
 from zerver.lib.upload import get_avatar_url
-from zerver.lib.upload.base import MEDIUM_AVATAR_SIZE
 from zerver.lib.url_encoding import append_url_query_string
 from zerver.models import UserProfile
 
diff --git a/zerver/lib/import_realm.py b/zerver/lib/import_realm.py
index 155c8c9e63..8481c87a07 100644
--- a/zerver/lib/import_realm.py
+++ b/zerver/lib/import_realm.py
@@ -32,9 +32,10 @@ from zerver.lib.push_notifications import sends_notifications_directly
 from zerver.lib.remote_server import maybe_enqueue_audit_log_upload
 from zerver.lib.server_initialization import create_internal_realm, server_initialized
 from zerver.lib.streams import render_stream_description
+from zerver.lib.thumbnail import BadImageError
 from zerver.lib.timestamp import datetime_to_timestamp
 from zerver.lib.upload import upload_backend
-from zerver.lib.upload.base import BadImageError, sanitize_name
+from zerver.lib.upload.base import sanitize_name
 from zerver.lib.upload.s3 import get_bucket
 from zerver.lib.user_counts import realm_user_count_by_role
 from zerver.lib.user_groups import create_system_user_groups_for_realm
diff --git a/zerver/lib/thumbnail.py b/zerver/lib/thumbnail.py
index 2822d24c20..ba2afba8ff 100644
--- a/zerver/lib/thumbnail.py
+++ b/zerver/lib/thumbnail.py
@@ -1,8 +1,28 @@
+import io
+from typing import Optional, Tuple
 from urllib.parse import urljoin
 
 from django.utils.http import url_has_allowed_host_and_scheme
+from django.utils.translation import gettext as _
+from PIL import GifImagePlugin, Image, ImageOps, PngImagePlugin
+from PIL.Image import DecompressionBombError
 
 from zerver.lib.camo import get_camo_url
+from zerver.lib.exceptions import ErrorCode, JsonableError
+
+DEFAULT_AVATAR_SIZE = 100
+MEDIUM_AVATAR_SIZE = 500
+DEFAULT_EMOJI_SIZE = 64
+
+# These sizes were selected based on looking at the maximum common
+# sizes in a library of animated custom emoji, balanced against the
+# network cost of very large emoji images.
+MAX_EMOJI_GIF_SIZE = 128
+MAX_EMOJI_GIF_FILE_SIZE_BYTES = 128 * 1024 * 1024  # 128 kb
+
+
+class BadImageError(JsonableError):
+    code = ErrorCode.BAD_IMAGE
 
 
 def user_uploads_or_external(url: str) -> bool:
@@ -17,3 +37,124 @@ def generate_thumbnail_url(path: str, size: str = "0x0") -> str:
     if url_has_allowed_host_and_scheme(path, allowed_hosts=None):
         return path
     return get_camo_url(path)
+
+
+def resize_avatar(image_data: bytes, size: int = DEFAULT_AVATAR_SIZE) -> bytes:
+    try:
+        im = Image.open(io.BytesIO(image_data))
+        im = ImageOps.exif_transpose(im)
+        im = ImageOps.fit(im, (size, size), Image.Resampling.LANCZOS)
+    except OSError:
+        raise BadImageError(_("Could not decode image; did you upload an image file?"))
+    except DecompressionBombError:
+        raise BadImageError(_("Image size exceeds limit."))
+    out = io.BytesIO()
+    if im.mode == "CMYK":
+        im = im.convert("RGB")
+    im.save(out, format="png")
+    return out.getvalue()
+
+
+def resize_logo(image_data: bytes) -> bytes:
+    try:
+        im = Image.open(io.BytesIO(image_data))
+        im = ImageOps.exif_transpose(im)
+        im.thumbnail((8 * DEFAULT_AVATAR_SIZE, DEFAULT_AVATAR_SIZE), Image.Resampling.LANCZOS)
+    except OSError:
+        raise BadImageError(_("Could not decode image; did you upload an image file?"))
+    except DecompressionBombError:
+        raise BadImageError(_("Image size exceeds limit."))
+    out = io.BytesIO()
+    if im.mode == "CMYK":
+        im = im.convert("RGB")
+    im.save(out, format="png")
+    return out.getvalue()
+
+
+def resize_animated(im: Image.Image, size: int = DEFAULT_EMOJI_SIZE) -> bytes:
+    assert im.n_frames > 1
+    frames = []
+    duration_info = []
+    disposals = []
+    # If 'loop' info is not set then loop for infinite number of times.
+    loop = im.info.get("loop", 0)
+    for frame_num in range(im.n_frames):
+        im.seek(frame_num)
+        new_frame = im.copy()
+        new_frame.paste(im, (0, 0), im.convert("RGBA"))
+        new_frame = ImageOps.pad(new_frame, (size, size), Image.Resampling.LANCZOS)
+        frames.append(new_frame)
+        if im.info.get("duration") is None:  # nocoverage
+            raise BadImageError(_("Corrupt animated image."))
+        duration_info.append(im.info["duration"])
+        if isinstance(im, GifImagePlugin.GifImageFile):
+            disposals.append(
+                im.disposal_method  # type: ignore[attr-defined]  # private member missing from stubs
+            )
+        elif isinstance(im, PngImagePlugin.PngImageFile):
+            disposals.append(im.info.get("disposal", PngImagePlugin.Disposal.OP_NONE))
+        else:  # nocoverage
+            raise BadImageError(_("Unknown animated image format."))
+    out = io.BytesIO()
+    frames[0].save(
+        out,
+        save_all=True,
+        optimize=False,
+        format=im.format,
+        append_images=frames[1:],
+        duration=duration_info,
+        disposal=disposals,
+        loop=loop,
+    )
+
+    return out.getvalue()
+
+
+def resize_emoji(
+    image_data: bytes, size: int = DEFAULT_EMOJI_SIZE
+) -> Tuple[bytes, bool, Optional[bytes]]:
+    # This function returns three values:
+    # 1) Emoji image data.
+    # 2) If emoji is gif i.e. animated.
+    # 3) If is animated then return still image data i.e. first frame of gif.
+
+    try:
+        im = Image.open(io.BytesIO(image_data))
+        image_format = im.format
+        if getattr(im, "n_frames", 1) > 1:
+            # There are a number of bugs in Pillow which cause results
+            # in resized images being broken. To work around this we
+            # only resize under certain conditions to minimize the
+            # chance of creating ugly images.
+            should_resize = (
+                im.size[0] != im.size[1]  # not square
+                or im.size[0] > MAX_EMOJI_GIF_SIZE  # dimensions too large
+                or len(image_data) > MAX_EMOJI_GIF_FILE_SIZE_BYTES  # filesize too large
+            )
+
+            # Generate a still image from the first frame.  Since
+            # we're converting the format to PNG anyway, we resize unconditionally.
+            still_image = im.copy()
+            still_image.seek(0)
+            still_image = ImageOps.exif_transpose(still_image)
+            still_image = ImageOps.fit(still_image, (size, size), Image.Resampling.LANCZOS)
+            out = io.BytesIO()
+            still_image.save(out, format="PNG")
+            still_image_data = out.getvalue()
+
+            if should_resize:
+                image_data = resize_animated(im, size)
+
+            return image_data, True, still_image_data
+        else:
+            # Note that this is essentially duplicated in the
+            # still_image code path, above.
+            im = ImageOps.exif_transpose(im)
+            im = ImageOps.fit(im, (size, size), Image.Resampling.LANCZOS)
+            out = io.BytesIO()
+            im.save(out, format=image_format)
+            return out.getvalue(), False, None
+    except OSError:
+        raise BadImageError(_("Could not decode image; did you upload an image file?"))
+    except DecompressionBombError:
+        raise BadImageError(_("Image size exceeds limit."))
diff --git a/zerver/lib/upload/base.py b/zerver/lib/upload/base.py
index 84592d430c..d5e76c1599 100644
--- a/zerver/lib/upload/base.py
+++ b/zerver/lib/upload/base.py
@@ -1,29 +1,12 @@
-import io
 import os
 import re
 import unicodedata
 from datetime import datetime
 from typing import IO, Any, BinaryIO, Callable, Iterator, List, Optional, Tuple
 
-from django.utils.translation import gettext as _
-from PIL import GifImagePlugin, Image, ImageOps, PngImagePlugin
-from PIL.Image import DecompressionBombError
-
-from zerver.lib.exceptions import ErrorCode, JsonableError
 from zerver.models import Attachment, Realm, UserProfile
 from zerver.models.users import is_cross_realm_bot_email
 
-DEFAULT_AVATAR_SIZE = 100
-MEDIUM_AVATAR_SIZE = 500
-DEFAULT_EMOJI_SIZE = 64
-
-# These sizes were selected based on looking at the maximum common
-# sizes in a library of animated custom emoji, balanced against the
-# network cost of very large emoji images.
-MAX_EMOJI_GIF_SIZE = 128
-MAX_EMOJI_GIF_FILE_SIZE_BYTES = 128 * 1024 * 1024  # 128 kb
-
-
 INLINE_MIME_TYPES = [
     "application/pdf",
     "audio/aac",
@@ -66,131 +49,6 @@ def sanitize_name(value: str) -> str:
     return value
 
 
-class BadImageError(JsonableError):
-    code = ErrorCode.BAD_IMAGE
-
-
-def resize_avatar(image_data: bytes, size: int = DEFAULT_AVATAR_SIZE) -> bytes:
-    try:
-        im = Image.open(io.BytesIO(image_data))
-        im = ImageOps.exif_transpose(im)
-        im = ImageOps.fit(im, (size, size), Image.Resampling.LANCZOS)
-    except OSError:
-        raise BadImageError(_("Could not decode image; did you upload an image file?"))
-    except DecompressionBombError:
-        raise BadImageError(_("Image size exceeds limit."))
-    out = io.BytesIO()
-    if im.mode == "CMYK":
-        im = im.convert("RGB")
-    im.save(out, format="png")
-    return out.getvalue()
-
-
-def resize_logo(image_data: bytes) -> bytes:
-    try:
-        im = Image.open(io.BytesIO(image_data))
-        im = ImageOps.exif_transpose(im)
-        im.thumbnail((8 * DEFAULT_AVATAR_SIZE, DEFAULT_AVATAR_SIZE), Image.Resampling.LANCZOS)
-    except OSError:
-        raise BadImageError(_("Could not decode image; did you upload an image file?"))
-    except DecompressionBombError:
-        raise BadImageError(_("Image size exceeds limit."))
-    out = io.BytesIO()
-    if im.mode == "CMYK":
-        im = im.convert("RGB")
-    im.save(out, format="png")
-    return out.getvalue()
-
-
-def resize_animated(im: Image.Image, size: int = DEFAULT_EMOJI_SIZE) -> bytes:
-    assert im.n_frames > 1
-    frames = []
-    duration_info = []
-    disposals = []
-    # If 'loop' info is not set then loop for infinite number of times.
-    loop = im.info.get("loop", 0)
-    for frame_num in range(im.n_frames):
-        im.seek(frame_num)
-        new_frame = im.copy()
-        new_frame.paste(im, (0, 0), im.convert("RGBA"))
-        new_frame = ImageOps.pad(new_frame, (size, size), Image.Resampling.LANCZOS)
-        frames.append(new_frame)
-        if im.info.get("duration") is None:  # nocoverage
-            raise BadImageError(_("Corrupt animated image."))
-        duration_info.append(im.info["duration"])
-        if isinstance(im, GifImagePlugin.GifImageFile):
-            disposals.append(
-                im.disposal_method  # type: ignore[attr-defined]  # private member missing from stubs
-            )
-        elif isinstance(im, PngImagePlugin.PngImageFile):
-            disposals.append(im.info.get("disposal", PngImagePlugin.Disposal.OP_NONE))
-        else:  # nocoverage
-            raise BadImageError(_("Unknown animated image format."))
-    out = io.BytesIO()
-    frames[0].save(
-        out,
-        save_all=True,
-        optimize=False,
-        format=im.format,
-        append_images=frames[1:],
-        duration=duration_info,
-        disposal=disposals,
-        loop=loop,
-    )
-
-    return out.getvalue()
-
-
-def resize_emoji(
-    image_data: bytes, size: int = DEFAULT_EMOJI_SIZE
-) -> Tuple[bytes, bool, Optional[bytes]]:
-    # This function returns three values:
-    # 1) Emoji image data.
-    # 2) If emoji is gif i.e. animated.
-    # 3) If is animated then return still image data i.e. first frame of gif.
-
-    try:
-        im = Image.open(io.BytesIO(image_data))
-        image_format = im.format
-        if getattr(im, "n_frames", 1) > 1:
-            # There are a number of bugs in Pillow which cause results
-            # in resized images being broken. To work around this we
-            # only resize under certain conditions to minimize the
-            # chance of creating ugly images.
-            should_resize = (
-                im.size[0] != im.size[1]  # not square
-                or im.size[0] > MAX_EMOJI_GIF_SIZE  # dimensions too large
-                or len(image_data) > MAX_EMOJI_GIF_FILE_SIZE_BYTES  # filesize too large
-            )
-
-            # Generate a still image from the first frame.  Since
-            # we're converting the format to PNG anyway, we resize unconditionally.
-            still_image = im.copy()
-            still_image.seek(0)
-            still_image = ImageOps.exif_transpose(still_image)
-            still_image = ImageOps.fit(still_image, (size, size), Image.Resampling.LANCZOS)
-            out = io.BytesIO()
-            still_image.save(out, format="PNG")
-            still_image_data = out.getvalue()
-
-            if should_resize:
-                image_data = resize_animated(im, size)
-
-            return image_data, True, still_image_data
-        else:
-            # Note that this is essentially duplicated in the
-            # still_image code path, above.
-            im = ImageOps.exif_transpose(im)
-            im = ImageOps.fit(im, (size, size), Image.Resampling.LANCZOS)
-            out = io.BytesIO()
-            im.save(out, format=image_format)
-            return out.getvalue(), False, None
-    except OSError:
-        raise BadImageError(_("Could not decode image; did you upload an image file?"))
-    except DecompressionBombError:
-        raise BadImageError(_("Image size exceeds limit."))
-
-
 class ZulipUploadBackend:
     # Message attachment uploads
     def get_public_upload_root_url(self) -> str:
diff --git a/zerver/lib/upload/local.py b/zerver/lib/upload/local.py
index 0a18ef912a..9e8d0c59f5 100644
--- a/zerver/lib/upload/local.py
+++ b/zerver/lib/upload/local.py
@@ -10,16 +10,9 @@ from django.conf import settings
 from typing_extensions import override
 
 from zerver.lib.avatar_hash import user_avatar_path
+from zerver.lib.thumbnail import MEDIUM_AVATAR_SIZE, resize_avatar, resize_emoji, resize_logo
 from zerver.lib.timestamp import timestamp_to_datetime
-from zerver.lib.upload.base import (
-    MEDIUM_AVATAR_SIZE,
-    ZulipUploadBackend,
-    create_attachment,
-    resize_avatar,
-    resize_emoji,
-    resize_logo,
-    sanitize_name,
-)
+from zerver.lib.upload.base import ZulipUploadBackend, create_attachment, sanitize_name
 from zerver.lib.utils import assert_is_not_none
 from zerver.models import Realm, RealmEmoji, UserProfile
 
diff --git a/zerver/lib/upload/s3.py b/zerver/lib/upload/s3.py
index 98ed7de301..185dc4a270 100644
--- a/zerver/lib/upload/s3.py
+++ b/zerver/lib/upload/s3.py
@@ -14,14 +14,11 @@ from typing_extensions import override
 
 from zerver.lib.avatar_hash import user_avatar_path
 from zerver.lib.mime_types import guess_type
+from zerver.lib.thumbnail import MEDIUM_AVATAR_SIZE, resize_avatar, resize_emoji, resize_logo
 from zerver.lib.upload.base import (
     INLINE_MIME_TYPES,
-    MEDIUM_AVATAR_SIZE,
     ZulipUploadBackend,
     create_attachment,
-    resize_avatar,
-    resize_emoji,
-    resize_logo,
     sanitize_name,
 )
 from zerver.models import Realm, RealmEmoji, UserProfile
diff --git a/zerver/tests/test_auth_backends.py b/zerver/tests/test_auth_backends.py
index 050d72edcd..ffd753c4b0 100644
--- a/zerver/tests/test_auth_backends.py
+++ b/zerver/tests/test_auth_backends.py
@@ -92,8 +92,8 @@ from zerver.lib.test_helpers import (
     read_test_image_file,
     use_s3_backend,
 )
+from zerver.lib.thumbnail import DEFAULT_AVATAR_SIZE, MEDIUM_AVATAR_SIZE, resize_avatar
 from zerver.lib.types import Validator
-from zerver.lib.upload.base import DEFAULT_AVATAR_SIZE, MEDIUM_AVATAR_SIZE, resize_avatar
 from zerver.lib.user_groups import is_user_in_group
 from zerver.lib.users import get_all_api_keys, get_api_key, get_users_for_api
 from zerver.lib.utils import assert_is_not_none
diff --git a/zerver/tests/test_realm_emoji.py b/zerver/tests/test_realm_emoji.py
index f266284fc1..01a7aab44b 100644
--- a/zerver/tests/test_realm_emoji.py
+++ b/zerver/tests/test_realm_emoji.py
@@ -8,7 +8,7 @@ from zerver.actions.users import do_change_user_role
 from zerver.lib.exceptions import JsonableError
 from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import get_test_image_file
-from zerver.lib.upload.base import BadImageError
+from zerver.lib.thumbnail import BadImageError
 from zerver.models import Realm, RealmEmoji, UserProfile
 from zerver.models.realms import CommonPolicyEnum, get_realm
 
diff --git a/zerver/tests/test_transfer.py b/zerver/tests/test_transfer.py
index e1bc8cf709..bdf10e12be 100644
--- a/zerver/tests/test_transfer.py
+++ b/zerver/tests/test_transfer.py
@@ -13,6 +13,7 @@ from zerver.lib.test_helpers import (
     get_test_image_file,
     read_test_image_file,
 )
+from zerver.lib.thumbnail import resize_emoji
 from zerver.lib.transfer import (
     transfer_avatars_to_s3,
     transfer_emoji_to_s3,
@@ -20,7 +21,6 @@ from zerver.lib.transfer import (
     transfer_uploads_to_s3,
 )
 from zerver.lib.upload import upload_message_attachment
-from zerver.lib.upload.base import resize_emoji
 from zerver.models import Attachment, RealmEmoji
 
 
diff --git a/zerver/tests/test_upload.py b/zerver/tests/test_upload.py
index df874d26f6..4b10ec341d 100644
--- a/zerver/tests/test_upload.py
+++ b/zerver/tests/test_upload.py
@@ -37,8 +37,9 @@ from zerver.lib.test_helpers import (
     ratelimit_rule,
     read_test_image_file,
 )
+from zerver.lib.thumbnail import BadImageError, resize_emoji
 from zerver.lib.upload import upload_message_attachment
-from zerver.lib.upload.base import BadImageError, ZulipUploadBackend, resize_emoji, sanitize_name
+from zerver.lib.upload.base import ZulipUploadBackend, sanitize_name
 from zerver.lib.upload.local import LocalUploadBackend
 from zerver.lib.upload.s3 import S3UploadBackend
 from zerver.lib.users import get_api_key
@@ -1422,15 +1423,15 @@ class EmojiTest(UploadSerializeMixin, ZulipTestCase):
             animated_large_img_data = read_test_image_file(f"animated_large_img.{img_format}")
 
             # Test an image larger than max is resized
-            with patch("zerver.lib.upload.base.MAX_EMOJI_GIF_SIZE", 128):
+            with patch("zerver.lib.thumbnail.MAX_EMOJI_GIF_SIZE", 128):
                 test_resize()
 
             # Test an image file larger than max is resized
-            with patch("zerver.lib.upload.base.MAX_EMOJI_GIF_FILE_SIZE_BYTES", 3 * 1024 * 1024):
+            with patch("zerver.lib.thumbnail.MAX_EMOJI_GIF_FILE_SIZE_BYTES", 3 * 1024 * 1024):
                 test_resize()
 
             # Test an image smaller than max and smaller than file size max is not resized
-            with patch("zerver.lib.upload.base.MAX_EMOJI_GIF_SIZE", 512):
+            with patch("zerver.lib.thumbnail.MAX_EMOJI_GIF_SIZE", 512):
                 test_resize(size=256)
 
         # Test a non-animated GIF image which does need to be resized
diff --git a/zerver/tests/test_upload_local.py b/zerver/tests/test_upload_local.py
index 156524ddf5..39d027550c 100644
--- a/zerver/tests/test_upload_local.py
+++ b/zerver/tests/test_upload_local.py
@@ -10,6 +10,7 @@ import zerver.lib.upload
 from zerver.lib.avatar_hash import user_avatar_path
 from zerver.lib.test_classes import UploadSerializeMixin, ZulipTestCase
 from zerver.lib.test_helpers import get_test_image_file, read_test_image_file
+from zerver.lib.thumbnail import DEFAULT_EMOJI_SIZE, MEDIUM_AVATAR_SIZE, resize_avatar
 from zerver.lib.upload import (
     all_message_attachments,
     delete_export_tarball,
@@ -20,7 +21,6 @@ from zerver.lib.upload import (
     upload_export_tarball,
     upload_message_attachment,
 )
-from zerver.lib.upload.base import DEFAULT_EMOJI_SIZE, MEDIUM_AVATAR_SIZE, resize_avatar
 from zerver.lib.upload.local import write_local_file
 from zerver.models import Attachment, RealmEmoji
 from zerver.models.realms import get_realm
diff --git a/zerver/tests/test_upload_s3.py b/zerver/tests/test_upload_s3.py
index 76e032a0a2..7474072e71 100644
--- a/zerver/tests/test_upload_s3.py
+++ b/zerver/tests/test_upload_s3.py
@@ -20,6 +20,12 @@ from zerver.lib.test_helpers import (
     read_test_image_file,
     use_s3_backend,
 )
+from zerver.lib.thumbnail import (
+    DEFAULT_AVATAR_SIZE,
+    DEFAULT_EMOJI_SIZE,
+    MEDIUM_AVATAR_SIZE,
+    resize_avatar,
+)
 from zerver.lib.upload import (
     all_message_attachments,
     delete_export_tarball,
@@ -29,12 +35,6 @@ from zerver.lib.upload import (
     upload_export_tarball,
     upload_message_attachment,
 )
-from zerver.lib.upload.base import (
-    DEFAULT_AVATAR_SIZE,
-    DEFAULT_EMOJI_SIZE,
-    MEDIUM_AVATAR_SIZE,
-    resize_avatar,
-)
 from zerver.lib.upload.s3 import S3UploadBackend
 from zerver.models import Attachment, RealmEmoji, UserProfile
 from zerver.models.realms import get_realm