diff --git a/config/config.exs b/config/config.exs
index 85a84208c..e0a5eccb1 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -167,7 +167,10 @@ config :mime, :types, %{
   "application/xrd+xml" => ["xrd+xml"],
   "application/jrd+json" => ["jrd+json"],
   "application/activity+json" => ["activity+json"],
-  "application/ld+json" => ["activity+json"]
+  "application/ld+json" => ["activity+json"],
+  # Can be removed when bumping MIME past 2.0.5
+  # see https://akkoma.dev/AkkomaGang/akkoma/issues/657
+  "image/apng" => ["apng"]
 }
 
 config :mime, :extensions, %{
diff --git a/test/pleroma/web/activity_pub/object_validators/attachment_validator_test.exs b/test/pleroma/web/activity_pub/object_validators/attachment_validator_test.exs
index 9150b8d41..f8dec09d3 100644
--- a/test/pleroma/web/activity_pub/object_validators/attachment_validator_test.exs
+++ b/test/pleroma/web/activity_pub/object_validators/attachment_validator_test.exs
@@ -11,6 +11,23 @@ defmodule Pleroma.Web.ActivityPub.ObjectValidators.AttachmentValidatorTest do
   import Pleroma.Factory
 
   describe "attachments" do
+    test "works with apng" do
+      attachment =
+        %{
+          "mediaType" => "image/apng",
+          "name" => "",
+          "type" => "Document",
+          "url" =>
+            "https://media.misskeyusercontent.com/io/2859c26e-cd43-4550-848b-b6243bc3fe28.apng"
+        }
+
+      assert {:ok, attachment} =
+               AttachmentValidator.cast_and_validate(attachment)
+               |> Ecto.Changeset.apply_action(:insert)
+
+      assert attachment.mediaType == "image/apng"
+    end
+
     test "works with honkerific attachments" do
       attachment = %{
         "mediaType" => "",