diff --git a/activities/views/compose.py b/activities/views/compose.py
index d5d034b..313fe74 100644
--- a/activities/views/compose.py
+++ b/activities/views/compose.py
@@ -1,4 +1,5 @@
 from django import forms
+from django.conf import settings
 from django.core.exceptions import PermissionDenied
 from django.shortcuts import get_object_or_404, redirect, render
 from django.utils.decorators import method_decorator
@@ -158,10 +159,12 @@ class ImageUpload(FormView):
 
         def clean_image(self):
             value = self.cleaned_data["image"]
-            if value.size > 1024 * 1024 * 10:
+            max_mb = settings.SETUP.MEDIA_MAX_IMAGE_FILESIZE_MB
+            max_bytes = max_mb * 1024 * 1024
+            if value.size > max_bytes:
                 # Erase the file from our data to stop trying to show it again
                 self.files = {}
-                raise forms.ValidationError("File must be 10MB or less")
+                raise forms.ValidationError(f"File must be {max_mb}MB or less")
             return value
 
     def form_invalid(self, form):
diff --git a/takahe/settings.py b/takahe/settings.py
index 15f30ee..89d4d3a 100644
--- a/takahe/settings.py
+++ b/takahe/settings.py
@@ -94,6 +94,11 @@ class Settings(BaseSettings):
     MEDIA_ROOT: str = str(BASE_DIR / "media")
     MEDIA_BACKEND: Optional[MediaBackendUrl] = None
 
+    #: Maximum filesize when uploading images. Increasing this may increase memory utilization
+    #: because all images with a dimension greater than 2000px are resized to meet that limit, which
+    #: is necessary for compatibility with Mastodon’s image proxy.
+    MEDIA_MAX_IMAGE_FILESIZE_MB: int = 10
+
     #: Request timeouts to use when talking to other servers Either
     #: float or tuple of floats for (connect, read, write, pool)
     REMOTE_TIMEOUT: float | tuple[float, float, float, float] = 5.0