Hey, guys. I'm trying to learn to make good tilesets and sprite and a friend of mine pointed me to Krata (free painting program) and it's "Wrap" function. It makes tiling SO much easier! Basically, if you push W key, the image you are working on tiles AND updates in real time. Not only that, you can work on any of the tiled copies of the image seamlessly. I've started making something like this myself a while ago w/ javascript and HTML five, but now that I know Krita does exactly what I was trying to do, I don't have to do it. Yey!
Here's a video: https://krita.org/item/new-wraparound-tool/
Here's a video: https://krita.org/item/new-wraparound-tool/