Change to using heic-convert which is more common than mogrify supporting these files

lib/pleroma/application_requirements.ex

@@ -163,7 +163,7 @@ defmodule Pleroma.ApplicationRequirements do
       check_filter(Pleroma.Upload.Filters.Exiftool, "exiftool"),
       check_filter(Pleroma.Upload.Filters.Mogrify, "mogrify"),
       check_filter(Pleroma.Upload.Filters.Mogrifun, "mogrify"),
-      check_filter(Pleroma.Upload.Filters.HeifToJpeg, "mogrify")
+      check_filter(Pleroma.Upload.Filters.HeifToJpeg, "heif-convert")
     ]
 
     preview_proxy_commands_status =

lib/pleroma/upload/filter/heif_to_jpeg.ex

@@ -29,20 +29,18 @@ defmodule Pleroma.Upload.Filter.HeifToJpeg do
   def filter(_), do: {:ok, :noop}
 
   defp convert(tempfile) do
-    # cannot save in place when changing format, so we have to use a tmp file
-    # https://github.com/route/mogrify/issues/77
-    # also need a valid extension or it gets confused
-
     with_extension = tempfile <> ".heic"
+    jpeg = tempfile <> ".jpg"
+
     File.rename!(tempfile, with_extension)
 
-    %{path: converted} =
-      with_extension
-      |> Mogrify.open()
-      |> Mogrify.format("jpg")
-      |> Mogrify.save()
+    convert_cmd =
+      "heif-convert #{with_extension} #{jpeg}"
+      |> String.to_charlist()
+
+    :os.cmd(convert_cmd)
 
     File.rm!(with_extension)
-    File.rename!(converted, tempfile)
+    File.rename!(jpeg, tempfile)
   end
 end

test/pleroma/upload/filter/heif_to_jpeg_test.exs

@@ -7,7 +7,7 @@ defmodule Pleroma.Upload.Filter.HeifToJpegTest do
   alias Pleroma.Upload.Filter
 
   test "apply HeicToJpeg filter" do
-    assert Pleroma.Utils.command_available?("mogrify")
+    assert Pleroma.Utils.command_available?("heif-convert")
 
     File.cp!(
       "test/fixtures/image.heic",