you can do that a couple ways.... most ways require opening the image in a photo editor program of some type...(psp, photoshop, ulead, photomax, whatever) 1. then using a crop tool, select a part of the image you want people to see in the thumbnail and crop... resize as needed to fit (i believe it's 150x150) OR 2. In that editor (and the how depends on the which one) Just resize the whole image to the size necessary (am sure it's in AS's link ^^^^^ up there) save it with a different name and upload... to add one to a picture already in your gallery, go to your gallery, click the "EDIT" button under it, you can replace the picture with a newer one, add or change a thumbnail, edit details, etc... have fun!