I just thought I'd bring this up and see if anyone else has noticed it. But upon uploading images I quite often get a very unhelpful "HTTP error" message. It normally happens on the first go at uploading something and although I think I have seen it before I believe its happening more frequently with WP SMush Pro. It's very frustrating when adding multiple images say for a gallery and it uploads some and not others and doesnt tell you which ones it hasnt uploaded just displays the HTTP error message which tells you nothing.
Thought it was worth bringing up as an observation to see if anyone else sees it.
Great plugin though.