Revert "Merge pull request #105 from code-dot-org/compress_images"

This reverts commit a4c19d23f1c8b06378d6c9a82f4306d3435b3765, reversing
changes made to 901993640a817097a256f1a2337b618f4ca18214.

The known problematic image is 1x1.gif, which makes it so that we dont see the play icon on our run button. Because we're worried about other subtle changes like this, I'm reverting the entire commit.