If you mean graphic images, then technoguyx is correct, however this should be in all about scratch.
If you mean squeak images, then you can open .image, .remix, .changes, and .source Just drag one of these onto scratch.exe.
"I'd love to change the world, but they haven't released the source code yet." Check out the latest version of Streak --> http://billy.scienceontheweb.net/Streak