It would be cool if the "x% smaller/ larger" text was colored depending on whether it's an improvement or not, so red for larger and green for smaller.
I agree. That's one of a few UI tweaks I intend to make to the files list. It's a little hard to digest what changed with an image at a glance. A few things I have in mind are:
Make the % change more obvious (w/ color and a small arrow to indicate larger or smaller).
Make the file name smaller (it's not that important).
Show image dimensions (original and new).
Make it clearer what the original and new file sizes are.
It would be cool if the "x% smaller/ larger" text was colored depending on whether it's an improvement or not, so red for larger and green for smaller.