this is a mazing TD
You’re only just beginning your project and already thinking this highly of it? sheesh!
I kid… I’m having trouble following everything you put out there but I’m going out on a limb here and just assuming you’re building a top-down grid of changeable tiles? If so, I’d just do plain colored squares for now. That’d be easy to do dynamically… or you can just draw out the squares in paint or wherever you choose to do your graphics and perhaps add small, crappy 1-minute touch-ups to them (crappy, and I stress crappy, little trees or rocks) here and there as you go just to get a feel of the direction. If you just save over the file you’re importing, changes on the fly should be no prob.
Next optional step might be to decide whether or not to give the tiles their possible edge combinations.. like where forest touches road or water.
^just a quick google image search for reference
I’d just make them solid colors for now (bucket fill green for forest, brown for road…) and worry about the pretty graphics later. You never know when you’ll want to change it up and possibly resize your game tiles. It’d be much easier if you had most of the code and gameplay fleshed out before-hand.
Just use your shitty programmer squares until you’re pretty sure you’re ready to make a commitment to graphics.
My apologies if this wasn’t what you were asking.