It's my mistake with the image importing—didn't notice that only .PNG files were supported and tried to import a .JPG (still would expect an error instead of crashing).
I'm very much a beginner at drawing, and I used to fix my proportions by moving parts of the image with selection; not a deal-breaker for me, though. Actually tried to kind of replicate it with a big 100% smudge brush today, but it looks like the smudge only samples the average color and not the image itself like photoshop does.
I will report further issues to the repository if I encounter any!
P.S. Was exploring your artstation yesterday, and discovered that I have a bunch of your paintings saved for a while, just didn't know it was you :)