My favorite image generator is RedKid.net. The images are easy to make, and the instructions are simple. "Type in your message and the image is created for you to do with as you please." All of the images on this article are generated from RedKid.
Start at the Sign Generator. You might want to bookmark the firect image generator page, because it can be tricky to find. From there, you can make pictures of fortune cookies, write words in alphabet soup, create the prophesy on a Magic 8 Ball, and write your own saying on a cake. Did your Super Bowl team lose? Just make a cake with the score you wish they'd gotten. You can write on an iPod screen, fill in the details on an iPhone or a Blackberry, or make your own sign.
Once you fill in the details on the image generator, the final picture will pop up for your approval. If you like it, right click on the picture and save it. If you want to edit the image, close the pop up and try again with the image editor.