Meet Doug (I really like his cool hat). I found Doug's picture here while looking for information on photo filters and PS actionscripts.
2. Create a new layer, move it to the bottom, flood fill it with any color of your choice, or use a pattern or background image, the choice is yours.
3. Create a new transparent layer, move it to the top, change layer mode to screen so you can see the image layer under it, flood fill that layer with black. (We're creating the selection mask on this layer)
4. Create your selection, and center it on the top "mask" layer filled with black, flood fill the new selection with white. Select - None.
5. Use Gaussian blur of 75px on the mask layer.
6. Filters - Artistic - Cubism: tile size 6, saturation 3.2, use background should be checked.
7. Edit - Cut the mask layer
8. On the image layer, right click in dialog, add mask layer, choose default settings. Edit - Paste. Anchor the floating selection.
9. Your done. But you can now replace the bottom background layer with ANYTHING you want simply by replacing it with a pattern, another image, or different color.
I'll be using the image of Doug to show how to create your own border layer mask using GIMP. Check out the video tutorial below (best viewed full screen):