I might be a dummy... what are you using them for? I guess if I wanted a 1" circle... I would go into photoshop... click the circle selection thing... at the top you can choose something to make the size what you want... type in 1" by 1", and I'd have a 1" circle. Then in a new layer, I'd paste my picture, make it whatever size... clip it by right clicking on the layer and select clip to layer, merge the layers, and wah lah!
Ok... y'alls way sounds easier!
I'm just used to digital scrapbooking and know some tricks.