If you want to edit (resize/covert...) your image, I recommend Irfanview. Irfanview is a good small software and it's FREE. I saw many of you used PAINT that came with windows, which gives you a BMP file. BMP files are big and do not have good quality.
** you should save image files in JPG format. Save as .GIF if they are animated or have few colors.**
OK, get your irfanview here:
http://www.irfanview.com/