When I put up images on my blog, I use png and jpeg. png's for those who want to use coloured versions of my images on different backgrounds, and I usually add a JPEG, lineart (or digi stamp) version for those that want a clear image to print out and colour in.

Simply put, if you had a sheet of paper with an apple image on it, you couldn't do to much with the image, as you would have to use the full sheet of paper, this would be the equivilant to a JPEG image.

Now if you cut out the apple image and throw away the rest of the paper , you can do lots of things with the image, put it on different backgrounds etc. This is the equvilent to a PNG image.

png's are good if you have a graphics program to manipulate them with, jpegs are good for just straight printing out.

Hope that explanation helps a little...

hugs Janie xxx