XML loading thumbnails and main image

hi guys! i just wanna ask, if it is possible to load a thumbnail image that you can set the dimension of each thumbs. what i mean is, i have an image 400x600. when it loads to thumbnails i want the size to be 80x100.-- and another image is 400x500 and when it loads to thumbs i want the size to be 80x80… Actually this is flash gallery with thumbnails, that looks like this. Four Seasons Hotel Los Angeles at Beverly Hills - Photo gallery.