TL;DR tilesets/graphics do not count as tools.

Hi, The word tool can be ambiguous. It can include many different things. But I don’t think it includes tilesets/graphics.

A criterion to define what is a tool could be simply what you would put in the Tools category of itch.io (what you are talking about would be into Game assets).

A tool could be something that allows you to make a tileset or use a tileset in the making of a game/animation/map.

I hope I’m clear enough, if not feel free to say. I also hope that it will make you want to create something that would fit in this jam and that could also be useful in your workflow. Otherwise I’m sure you can find other jams where you can post game art.