What are the correct sizes for each type of graphics?
From OHRRPGCE-Wiki
If you are planning on making your graphics in an external program and saving them as 4-bit (16-color) BMP files to import into your game, it is helpful to know the correct dimensions for each type of graphics.
Heroes...........32x40 Walkabout........20x20 Portraits........50x50 Small Enemies....34x34 Large Enemies....50x50 Huge Enemies.....80x80 Attacks..........50x50 Weapons..........24x24 Box borders......16x16 Backdrops......320x200 Tilesets.......320x200
Note that you do not have to get the size exactly right. If you are off by a little, you will still be able to import your pictures
Remember that a BMP file must be saved with only 16-colors (4-bit color depth) if you want to be able to import it, except for backgrounds and tilesets which must be saved in 24-bit or 8-bit color depth.
If you are importing in full-spriteset mode (CTRL+F) here are the sizes for spritesets.
Heroes...........256x40 Walkabout........160x20 Attacks..........150x50 Weapons..........48x24 Box borders......256x16