If it helps I can upload the original uncompressed image so someone could look at both.
Although, since I could repo on our instance of nodebb over at plutonium with both the compressed and uncompressed image, the bug seems to be caused by something unrelated to the compression itself
This likely cropped up because flag actions now use the v3 API instead of socket.io, so it could be it overloaded the backend, which started sending 503s.