I have had a lot of fun using the different image generators to manipulate images. I particularly liked the idea of turning photo's and other visuals into puzzles. This would be great to use with lower ability classes, you could create out a puzzle out of anything - a text type, visual text, picture book, film review. It helps to make the lessson more fun and engaging - rather than just reading a text - students in groups or as individuals put it together first. The site I turned my photo into a puzzle is http://bighugelabs.com/jigsaw.php
There are also lots of different other options, students can create posters of themselves as movie stars, pop stars, create magazine coves, calenadars etc - the opportunites are endless.
Also I liked using http://www.imagegenerator.org/ It had a lot of different ways to manipulate images with text and photos.
I also played with cool text http://cooltext.com/ and played around with it a bit. Though I feel I need to spend more time with all the links!