Images ???

Hello, I want to show a list of images ( but in a small size - should I use ImageCopyResized ? how ? ), existed in a directory ( they are uploaded to dir, and the name of each image is also inserted into a DataBase ), with a link to the respective image and real size. To work with images ( I think its the only way... ) I declare a Header telling that the content is an image, but the kind of image can be different (*.jpeg,*.png, *.gif, ...), so ( I think ...) should I have a different Headders ? My other problem is to show the small copied images in a page that already have other information(ex: the name of the user, for that I'm using sessions), so can I do it, is it possible ? Thanks Miguel Loureiro