Sometimes you need to clean up an image to import it into Boardmaker or you need to resize it to use it in a teacher made book or worksheet. I tend to use the two photo editors which have add ons in Firefox, Snip Shot and Picnik, but I also us Pixenate which has more complex tools and flauntR which embellishes as well as cleans up photos. Save these links to your book marks in case you need them.
Also VectorMagic is not a photo editor by turns images into high quality vector images like those in Boardmaker, perfect for picture you plan to import into Boardmaker. And Sporkforge which turns a photo into a sketch which is fun as well.