Resizing MCs without the border getting all funky

Is there a way? I need to give a thumbnail that I’m changing the size of a border, but to simply place a background movieclip behind it and resize it along with the thumbnail stretches out the borders and makes them all blurry. Is there a way to change the size the background movieclip so that it retains it’s normal-sized border? Or, if that doesn’t work, is there a different way to go about making my pictures have borders?