Put each on it's own layer, make the frame the top layer and erase the gray area in the middle of the frame.
Resize and place the 2nd layer where you want it and erase or mask the areas you don't want to show.
Just make the picture as a pattern for the line and draw the line around the second picture, to make the pattern of the first picture, appear as a frame for the second picture through the use of a simple line. I know I kind of suck in the explanation, but if you do manage to understand what I just said, do try.
Nice share. I have some image which are very precious but they not looks good without frames so i think if i will have frames around the images than it will get up more. I will use your tips and try to edit my photo.