Not 150 px grid. I reduced the file size to 150 ppi from 300 ppi. The grid is only 50 px now (from 100 px). I did a test save with what I've got so far and I got it down to 28 MB, but you can't zoom in really... it's blurry now.

How do people make these complex vtt maps? My computer can't handle this. Or Photoshop can't. I don't know which one is the problem. My machine isn't new, but I've got a i7 6700 3.41 GHz with 16 GB of RAM and a SSD for a hard drive. I've dedicated 80% of my RAM to Photoshop, but this map is not playing nicely.

@Redrobes, Foundry VTT. The "map" isn't that big. I guess it was. I had the dimensions at 12,000 px x 9,000 px, but I cut it in half. The FILE SIZE is what is big. I'm trying to merge some layers to cut down on size, but it didn't help much.

I appreciate y'all taking the time to respond.