I think everyone can agree that Photoshop is by far the best photo editing program out there but its far from free, its very expensive. If you don't have the money for photoshop that is ok there are quite a few FREE photo editing sites that require no downloads for you to play with. Cnet recently did a story on Photoshop alternatives and here is the basic rundown of them (plus a extra one):
Pixenate offers plenty of options, including straightening and adjustments. Other features include teeth-whitening by drawing a box around your subject's mouth and lightening a vaguely smile-shaped area, and interlacing, which adds horizontal lines and makes your picture look like a TV still. Most options show a respectably sized preview thumbnail. It's also a Facebook app.
Picture2Life animates images, in this case for social-network avatars and profile pictures. You can connect to sites such as Flickr and Facebook, and even add an extension to Firefox or IE to grab any image from the Web for editing.
If you don't want to sign up to Phixr, you can create a temporary account that lasts two hours, or the site supports OpenID. You can upload an image from your hard drive or from a URL, which means you can edit your Flickr or Facebook images.
Effects include the option to convert to black and white or sepia, and alter the brightness, saturation and contrast. The preview thumbnail isn't great for fine detail, but it does give you an overall idea of the effect. The most unusual feature is the ability to upload a scan of text and run optical character recognition.
LunaPic also creates animations from images, with snappy rotating cube and reflection animations that can be saved as animated gifs.
In an unusual but still intuitive twist, it saves your history as a sequence of thumbnails, so you can actually see and restore each edit. And unlike Photoshop it's not linear, so rather than only being able to hop backwards and forge on from that point with a new set of edits, losing a sequence of changes, you can hop to any edit at any time. The only thing to remember is that the thumbnails are numbered from right to left.
There aren't any layers, but you can paste a selection, move it around and even alter the transparency before clicking apply. You can also view the selection saved in your clipboard.
The Piki range of sites allows you to turn your images into clothing and even sell it online. PikiStrips creates comic strips from photos, adding captions and speech bubbles.
Not only does Sumo offer layers, you can also create more advanced layer features, such as drop shadow. It offers assorted blending and masking options, as well as levels and curves. In fact, it'll do pretty much everything you'd ever expect of a Photoshop alternative. And once you've created your masterpiece, you can show it off to the Sumo community with a free account.
Pixlr is a truly impressive Photoshop replacement with layers, history, levels and all the tools you'd expect. As well as the usual brushes and boxes, the toolbar also includes effects such as sponge and smudge tools, and distorting pinch and bloat options. The list of filters is one of the longest we've seen, including everything from scanlines and heatmap to a nifty tilt-shift effect.
Effects benefit from real-time previewing, which even with 12-megapixel photos only briefly lags. With Web-sized images, changes are previewed near-instantly.
For the unitiated, FotoFlexr is an online photo-editing tool that integrates effortlessly with Facebook, MySpace, Photobucket, Flickr and Picasa to edit or 'flex' your images. There are lots of distortion and colour effects, although some are more subtle than others. The 'beautify' menu even features a wrinkle-cream option, and there's the slightly freakish option to paste your face on to the head of a gorilla or Paris Hilton.
FotoFlexer even has that most essential and inconsequential of 2007 accessories: the Facebook app. Once you've loaded the app to your profile, you can click on your pictures and those of your friends to cartoonify, Warholify, or X-ray-ify, among others. FotoFlexer have also made their API available for integration into your own site. If you use photobucket then the "edit" button will allow you to edit your photos useing fotoflexer.