Imageoid is a free, simple service for adding a variety of effects to your images. To use Imageoid you just upload an image from your computer then choose the effect(s) you want to apply to it. You can combine effects if you like. If you don't like the way your image looks with a chosen effect, just click "reset" to start again. Imageoid can also be used to resize your image. Imageoid offers twenty-two effects that you can apply to your image. Below you can see the before and after of one of my images.

Thanks, Rhondda, for pointing this out. I can hardly wait to try it!