CMS Made Simple Forums

Hi....
We are using CMS as a web site for members of an art group.
CMS was installed by others, and I am just the "keeper" of the site and help others get organized and enter their bio's and paintings.
My question?
Images are fuzzy, when shown as a thumbnail and are also fuzzy when double clicked and enlarged.
Is there  something that should be done to the artist's image prior to downloading that can resolve this problem?
Thanks.

A link to the site might help us track down the issue. With artist's images I'd try to leave the image resizing and prep to a pro - I have a buddy who does that kind of thing for a living, and color-correcting alone can you nutty.