i read your tutorial on making a picture from a large size into a small size, but how do you change the sise when its reverse, i mean when a photo is small and i want to make it big. you see i have a picture i took of my cellphone and i want to put it on my computer desktop background as a wallpaper but i need to make the picture bigger because the image its too small. how can i make it bigger?

by the way, this is the tutorial i am talking about:

http://www.wallpaperama.com/forums/how-to-make-big-large-picture-files-smaller-size-images-reduce-make-smaller-t1035.html