Open up a PSD of the image you want to outline. This basically means that it should have a transparent background.
Go to ‘Selections’ > ‘Select All’. You should have something like this:
Now click and click the actual person in the picture. The person should be outlined like this:
Decide what colour you want your outline to be. I’m doing black. You need to open up a black image about 100 pixels wider and taller than your original. You could also use the floodfill bucket to create gradient or pattern outlines, it’s up to you.
Right-click your original image and choose ‘Copy’, then go over to your background image (the one you opened in step 4), choose ‘Paste as a new selection’, and position so it’s in the centre:
Go to ‘Selections’ > ‘Modify’ > ‘Expand’, and change the number depending on the size of your image and how thick you want the border. I’m using 3.
Now paste your image onto a patterned background and save. Remember, you can outline your image as many times as you like for different effects. Here are a couple I made: