images in themes not downloading/images not uploading

I downloaded WordPress with my web hoster using Fantastico. It seemed to go okay, until I installed some themes from my WordPress profile. I installed Twenty-Eleven, Twenty-Twelve and Weaver. The images from these themes are not showing, although I was able to browse images before installing these themes. Also, I cannot upload an file image for a background for my blog. I usually use Explorer, but I also tried Firefox and the images are not showing.