how do you merge two photos together?

[shucampbell21]

hey I'am trying to make a pic were it looks like I'm giving myself a high five (just a dumb picture to make) so when I get the two pics together how do I get rid of the boarder between so it looks like its one picture

[Tom]

You need first to extend the size of the background image with the function : canvas size in the right clic or image menu.
Paste the second image on the first one : then you can erase the border with a selection or the erase tool
Adjust the position of the layer and the erase tool on the layer help you to refine the transition.