Why is the phone app so much easier than the desktop app?

This is the worst app I've used on my computer, none of the options are where you expect. It works the opposite of every computer app, things like undo are in odd places. Every time I use this app I feel like I have to re-learn every aspect of it. All I want to do, is to crop one picture, and add it on to another. I've done it countless times using this same app on my phone, yet doing it on a computer is an absolute chore. Nothing makes sense, its baffling and just an awful user experience. I shouldn't have to google and ask questions in order to figure out how to make a simple crop. 

The entire front end and user experience needs a total rehaul.