First, you need to make sure they are under 100kb in size. Next, they should be .jpg format. This can be achieved by resizing the image. This can also be done by changing the quality of the image. I'm not sure exactly how to explain it other than the fact that I use ArcSoft Photostufio 2000 SE. When I go to save the image I can choose the quality of the image before saving. Depending on your image program it most likely will be different to change the the image quality.