[tealtan]

This is really great!

But - another useful option would be mouse rollovers to switch between two images (which I think would work better than Onion Skin).

[weaksauce]

The swipe feature doesn't work for you? Onion skin is to gradually change the opacity of the new one while keeping the old one constant but below while swipe is a hard line difference that you can move.

[tealtan]

I like the swipe feature, but it's harder to grab and drag that tiny handle than to just roll over an image. With rollovers, I'd be able to flip through the two much more rapidly and simply.

Also, I should mention that Kaleidoscope is one of my favorite apps: http://www.kaleidoscopeapp.com/

[fanf2]

Yes, I often find blink comparison useful. A keypress to switch between opposite ends of the onionskin and swipe bars would do the trick.

[pavel_lishin]

In the short term, I bet a greasmonkey script could accomplish this fairly trivially.