For every example of crap Photoshopping – politicians and women’s magazine covers seem cursed by it – millions of other photos are routinely Photoshopped before going public, whether for purposes of retouching, compositing, conversion or production. The next time you see a picture that seems too dark, too smudgy or too brown, you’ll know why: it simply hasn’t been Photoshopped.

[theregister.co.uk...]
This five page article (with pics!) is a trip down memory lane. I've been using it since version 2, currently on ver 5 (have had no need to go further... my site needs are not that immense), but I can't think of a more useful tool for site graphics.

Disclaimer: I do use other image tools, but this is the one I come back to time and again.