Quickie: Best way to dynamically resize a border

I am going to make an image gallery that loads jpg’s. Around the jpg is going to be a border that resizes depending on the demensions of the image. I want the border to expand so that it encompasses the image, BUT i dont want the width of the border to change. SO, would this work:

Break the border up into 4 MC’s (topbar, bottombar, leftbar, rightbar), and have the topbar and bottombar’s width resize according to the jpg loaded, aswell as its _y postion change according to the height of the jpg, and have the side bars height resize according to the height of the jpg and its x position change according to the width of the jpg. If it did it right, could this result in a border that resizes depending on the demension of the dynamically loaded jpg, but the actualy width of the boarder all the way around stays the same? I’m thinking that I’m correct, but just wanted to make sure there wasnt any glaring problems before I procceded. THANKS!