Board Thread:Support Requests - Designing Your Wikia/@comment-44816-20140901203508/@comment-17033657-20140907205608

This is a common misconception...

The Theme Designer is saying that the file is too large. The image can be the right physical size, but the amount of bytes could be a bit too much. I think the limit is around 300 kilobytes. Use a simpler image, maybe tone down on the colors or so.