1 – Open your image and duplicate
2 - Close the original image as we don't need it anymore
3 - Go to: Layers > Load/Save Mask > Load Mask from disk and choose #182
Check - source luminance, fit to canvas, hide all mask
Click ok.
4 - Now on the mask layer, go to: Layers > Delete and answer yes to merge layers
5 - Layers > Merge > Merge Group
6 - Add a new layer
7 - Layers > Arrange > Send to the Bottom
8 - Choose a very light complimentary colour to your image, as your background colour
9 - Flood fill layer 2 with your chosen colour
10 - Layers > Merge Visible
11 - Selections > Select All
12 - Selections > Modify > Contract by 25
13 - Selections > Invert
14 - Effects > 3D Effects > Outer Bevel - see screen shot below
15 - Keep selected
16 - Effects > 3D Effects > Inner Bevel - see screen shot below
17 - Keep Selected
18 - Effects > Plugins > CPK Designs > Shadow Bevel
Settings: 44, 31 and 31
19 - Add decorative corners if you wish.