I may have mentioned this before, but I thought I would share again. I have found a great, FREE, online photo editor - www.picnik.com. I often have to take pics with no flash because using a flash on a white cake results in an overexposed pic (too much white). But if I take it indoors without the flash, it comes out too dark like the one below.
But, if you go to www.picnik.com, upload your image (or load it from Flickr or another photo sharing website), click on the Colors tab, click on the Neutral Picker button, and then place the medicine dropper on something in your picture that is supposed to be white or gray (in this example, I clicked on the white buttercream). And, voila! It's fixed.
My graphic designer friend tells me that PhotoShop has an autolevels feature or something like that, but PS is just too complicated for me.
They also have a lot of other cool editing features that are handy as well as fun. If you check out the newest pics in my photostream you can see how I've used some of these image manipulation techniques.
If you have any questions about using it, feel free to ask. There are no stupid questions.
Thanks! I've favorited the site. It's awesome