Lovely stuff, looking forward to keeping up with your photography adventures again!
Btw, a little trick that I use with photoshop is to just align using the numbers. So if I'm using 1200x800 images, they will be 1200 high by 800 wide (for portrait). I open both images, and select all/copy one. Then I go onto the other photograph and make the canvas size 1200x1610 (I double the width, then add 10 pixels for a gap, obviously the gap can be whatever you want). Make sure you extend the canvas from one side only, then you'll have a 1200x810 gap for the other image. CTRL+V, quickly drag the photo to the side and let it snap into place and hey presto you're done!