What is the right way in GD of using sprite/tiles sheets? Do you need to cut them by hand in another program and then use in GD? What is the easiest way to do it?
I think you could use the spritesheet tool in gd, however I haven’t tried it ever 
It’s under Projects/Image converters/decompose a spritesheet.
There’s even an option to make a colour transparent so might be helpful. 
Experimenting with it… Thanks for the tip!