Should I show a progressbar or a drawable for each item of a listview?

Question

There is a listview in my app, where I show a drawable for each item; since I retrieve those drawables from the internet it takes some times to load them, so I'm supposed to show the user a little indeterminate progress cycle for each drawable, until I got the picture. My question is: what should I show in the meantime? I mean, should I show an animation into the drawable (is it even possible?) or a progressbar overlapped to the drawable? There are fields of tutorial which explain how to create and customize a progressbar, but I wasn't able to find a guideline about what's best to do in these cases... Thank you for your answers.