Hi. I meant taking a large piece of artwork in Photoshop and using slices to export a series of smaller PNGs (like jigsaw pieces) and putting them back together on a layer in GDevelop (one object with multiple one-frame animations). Having a PNG of, say, 4000 pixels wide isn’t a good idea, so you chop it up into smaller rectangles instead.
Have a look at this thread, where CorianderGames talks about a large level he did for his game. He ended up chopping his Photoshop artwork into 32 x 32 pixels pieces to get the game to run well.
Don’t worry: that’s an extreme case because his artwork was particularly large. I’m using 300 x 300 ish pieces for the foreground art in my game and it seems to run nicely so far. I use a large tile for the parallax background - repeats horizontally only - and that seems to work well too.
Here’s some general image guidance from the GDevelop wiki. The second bullet point is particularly relevant to this discussion:
https://wiki.gdevelop.io/gdevelop5/tutorials/how-to-display-big-background
This one might be helpful too:
https://wiki.gdevelop.io/gdevelop5/tutorials/reduce-size-game