With this, you can take one image, move it around among these 2 screens positioned how you want it, this way it will tile perfectly between both screens on your 3DS. Then it will export the 2 images needed to put into YATA to make a seamless background for your Nintendo 3DS theme.
EDIT: Currently in production of the scrolling wallpaper side of the program.
Something I've noticed with YATA:
The Simulate feature in YATA doesnt seem to line up. I went back and checked all of my calculations and it lines up. Even in the PSD I am working on. Weird.
EDIT: I just tested my program and made a cropped pic and put it into YATA. Didnt line up as usual in the simulator for YATA but the results are correct as you can see:
Words may hurt more than fists, but fists speak more than words.