I'm putting this on Computery as well so EVERYONE can find this link!
Splashup is a free photo editing programme that works right on your website!
No need to download, and having had a little playaround, it seems a lot easier than Gimp (also free, which is more equivalent to Photoshop - and very hard to use if you are a newbie).
It will do everything the simpler graphics programmes can do, including resizing, adding layers, effects etc. Well worth a look, and just the job for anyone teetering on the bring of needing a graphics programme but dithering as to which one to buy.
You don't even need to register if you are working with images from your computer - although, if you do, you can save work in progress, files etc - and works with any browser. If you are registered, you can also get straight into your Flickr, Photobucket, Picasa, Smug Mug and Facebook account.