Hey, floof! Take a lookie at this checklist just to make sure everything is up to par! FH can be very finicky with heighmaps sometimes ;3
- 513 x 513
-Grayscale Mode (Can't just be grayscale, has to actually be in grayscale mode)
-No alpha channel
-One flattened layer
-You're saving as mapnameTerrain.png
-No spaces in the file name, spaces must be replaced with underscores _ (For example if your map is Pride Rock you save the terrain file as either PrideRockTerrain.png OR Pride_RockTerrain.png)