If a free copy of a 10-year-old Adobe Photoshop release wasn't for you—maybe your computer's too good for it, or perhaps you just wanna stick it to the man—don't worry. There are plenty of completely free alternatives; here are ten of the best.
The big daddy of free image-editing software, GIMP is a free ‘shop alternative for the power user. There's full support for layers and masks, a good range of sophisticated brush controls and even a rough content-aware fill via unofficial plugins like this. For those pining for Auntie Adobe, there's a version of GIMP called GIMPshop that sports all the GIMP functionality with a Photoshop-imitation layout.
Paint.NET is slightly less powerful than GIMP, but less unwieldy (more wieldy?). The interface I find to be more intuitive, and I spent far less time playing hunt-the-feature than I did in GIMP.
Pixlr is a deeply impressive web-based image editor - it's my go-to program when I'm away from my Photoshop-touting machine but still need to do the nasty to some poor unsuspecting image. Having three levels of editor - basic, intermediate and all-singing-all-dancing-layer-masking-power-clone-stamp-of-doom - makes it accessible to pretty much anyone, not exactly something you can say about Photoshop.
Like Pixlr, but trading less power for a gorgeous and easy-to-use interface. For image-editing beginners, this would be a sensible choice.
A decidedly power-user's tool. Its claim to fame is the use of vector graphics rather than bitmaps as the native format. If you pine for Photoshop's vector support like you pine for your nanny, Inkscape might just be the program for you. (Yes, I know, Photoshop's vector support isn't stellar, but it's still a lot better than GIMP.)
Seashore is a fairly basic image editor that's visually quite pleasing, with a UI that apparently "blends right in" with the rest of Mac OS X. You can make up your own mind on that, but the editor itself isn't bad. No editable text layers is annoying though.
Pixia is the English-language version of a popular Japanese image-editing programme. Once again, it's a power-user's tool. Although the interface isn't the most friendly or slick in the world - in fact, it feels slightly like being slapped in the face by Windows 95 - it has a good range of features, and was the best of these programs for stylus/digitiser support.
Photo Pos Pro (works quite well as a tongue-twister, by the way) is a Photoshop replacement that promises much, and delivers a little bit. The interface features cutting-edge Windows XP graphics, but it has a slightly confused purpose: on the one hand, it's trying to be a pro, Photoshop-style tool with dense menus and powerful options; on the other, it's still got a freaking "tip of the day" popping up, interrupting me and making me want to visit the inventor of pop-ups with a chainsaw and murderous intent.
Google's Picasa isn't a Photoshop competitor; regardless, it's got many of the same basic features as Photoshop, including a half-decent Clone Stamp replacement. If you're only looking to make image-wide corrections, with a few little re-touches here and there, this is a superb option. The photo-management and batch editing options are just a plus.
More of a basic image editor, Photoplus is relatively user-friendly but lacks the vast majority of features that the more advanced options sport. It also doesn't have keyboard shortcuts - one omission which drives me completely loopy after about 5 minutes. The pop-ups asking me to buy the full version weren't particularly attractive either.