I'm just gonna say it. I love these.
Quick howto and rules on tiles:
1. No tilesheet support. Each tile needs its own png file.
2. No mask color. Alpha all the transparent bits.
3. Power of two texture. 32x32 is prefered, 64x64 is possible, but discouraged.
If you want to test them its easy too.
Copy your tiles to game/modules/tome/data/gfx/*/ (replace * with npcs, objects, etc)
Go into your tome install directory, /game/modules/tome/data/general/*/*.lua files. Either add a image= line or edit the existing one to refer to your image. Most objects should already have image= tags.
Run ToME. If it complains or crashes, something went wrong, log should help.
The hard part may be finding examples of all your objects ingame
If you know how to diff files and you have made these modifications, you can send the patch directly to DG. Otherwise you can send the tiles directly to him and he will make the modifications. You may have to wait till he releases a new version or compile it from source to actually see your tiles ingame however.