diff --git a/netbox/extras/forms/model_forms.py b/netbox/extras/forms/model_forms.py
index f5833c334..dbcc8717a 100644
--- a/netbox/extras/forms/model_forms.py
+++ b/netbox/extras/forms/model_forms.py
@@ -22,7 +22,7 @@ from utilities.forms.fields import (
     DynamicModelMultipleChoiceField, JSONField, SlugField,
 )
 from utilities.forms.rendering import FieldSet, ObjectAttribute
-from utilities.forms.widgets import ChoicesWidget, HTMXSelect
+from utilities.forms.widgets import ChoicesWidget, ClearableFileInput, HTMXSelect
 from utilities.tables import get_table_for_model
 from virtualization.models import Cluster, ClusterGroup, ClusterType
 
@@ -784,6 +784,10 @@ class ImageAttachmentForm(forms.ModelForm):
         fields = [
             'image', 'name', 'description',
         ]
+        # Explicitly set 'image/avif' to support AVIF selection in Firefox
+        widgets = {
+            'image': ClearableFileInput(attrs={'accept': 'image/*,image/avif'}),
+        }
         help_texts = {
             'name': _("If no name is specified, the file name will be used.")
         }
diff --git a/netbox/extras/utils.py b/netbox/extras/utils.py
index 761f4affb..45c0729a4 100644
--- a/netbox/extras/utils.py
+++ b/netbox/extras/utils.py
@@ -78,7 +78,7 @@ def image_upload(instance, filename):
     """
     upload_dir = 'image-attachments'
     default_filename = 'unnamed'
-    allowed_img_extensions = ('bmp', 'gif', 'jpeg', 'jpg', 'png', 'webp')
+    allowed_img_extensions = ('avif', 'bmp', 'gif', 'jpeg', 'jpg', 'png', 'webp')
 
     # Normalize Windows paths and create a Path object.
     normalized_filename = str(filename).replace('\\', '/')