Step 4: copy bi flag image (Ctrl+A, Ctrl+C) and paste it into your photo (Ctrl+V)
Step 5: adjust the size of the bi flag using the ‘Free transform’ option (located under the ‘edit’ menu)
Step 6: adjust the transparency of your bi flag if you don’t like how it looks
Step 7: save your picture!
Congratulations you have your very own bi image!
I made some more semi-transparent pride flags in case anybody wants something other than bi! (including rainbow in case anybody wants to do something other than their facebook profile picture!)