My first observation was that it took me a moment to work out how to confirm the crop. The confirm button is unlabelled and in the top right of the screen - a place I would generally expect 'global' actions rather than an action crucial to my immediate task.

EDIT

Second observation - even more confused. I hadn't accepted the crop - instead I'd entered a new mode with no more editing possible - only the four unlabelled icons in the top right (you get the impression I really hate unlabelled icons? Google 'mystery meat'...)

So I'm trying to wrap my head around the conceptual model. I can do multiple things to my image - but the crop doesn't give me a preview until I accept all the edits. So how am I meant to crop then flip or some other combination?

Looks pretty good. Have you considered turning this into a Chrome extension?

I've not found a simple photo editor extension that I can use within Chrome. Ideally I'd just like to right click on photos, do simple crop/resize/quality/colour conversions and have the results available for insertion into gmail attachments or form uploads (via a temp URL perhaps?).

This would replace my current workflow...often I find myself receiving a set of images in gmail, downloading them, performing trivial manipulation with Windows photo editor or paintbrush, saving the results with sensible encoding/quality (some ppl forward me bitmaps...) then re-uploading the results.