How to make a webtoon in ibis paint

My webtoon canva size in ibis paint on is sometimes 1600 pixels wide x 3000 pixels long. I don't like to draw on one long file but instead like to draw in shorter file sizes. With shorter files I usually just draw 2-3 panels per file. When I upload it on webtoon canva or tapas their website stacks it up so it looks like I drew it on one long file.