Yes, one image per article would be ideal. I tested to make images as tall as my image editing program would allow (30,000px if I remember correctly), which worked absolutely fine, so there shouldn’t be a problem there.
It would be pretty nice to just be able to download a new issue directly on the device, but I would want to make sure there’s an archive available as well in that case.
Also, before I forget again, I want to mention one thing that was an inspiration to some degree: Lady of the Shard. It’s a mostly 1-bit pixel art comic that would almost work to just put on Playdate. I just think it’s really cool and even if it wouldn’t completely work with the display, I was thinking for a while that it would be cool to make something similar for Playdate, and then the idea for a zine just came to me. (Standalone comics in that style would also still be really cool.)