Peter Brunette

Thanks, Dan. You cleared that up for me very nicely.

When I use the Affinity Photo extension in Apple Photos, I get this message: "16MB change limit exceeded -- document will be flattened." This topic was raised in the forum a couple of years ago and some workarounds were suggested. However, nobody explained what "flattened" means. I'm using a 27-inch, 5K display, and I can't see the difference before and after the flattening. What exactly do I lose if I let Photos flatten the image?