What software do I need to do this?

[dormouse]

Well it looks like after a whole day futzing around with it, I see DungeonForge can do what I need. Although clumsily. It is free though, which means more money towards tiles and less towards tools.

But I can't get any of the png's that I made myself to show up on the selector without having to manually add a .tileinfo file for each graphic. Anyone have an inkling as to why?

Old thread; I'm afraid I didn't see it until now - I don't go looking for questions about DF in other forums very often. If it's OK, I will at least answer it now in case anyone else is ever interested. I don't remember the question being asked on the DF forum; it would have been answered fairly quickly if it had.

Objects can be placed on maps in DF without any tileinfo set. They can also be set to align with the grid.

But if you want to use them as tiles, the program needs to know how you want the image to tile. You may have a 200x200 image that you want just to use as a single tile (ie covering 1 square in the grid) - but you may want it to work as a 2x2 (covering 4 squares) or some different dimension. The tileinfo needs to be set, so that it knows what is wanted. You can do this in the program one image at a time, or you can add a tileinfo file manually; if you want tomake a folder of images tileable, then you can use the TTSTool (available on site) or you can run a batch script. Instructions for all these are on the site.

Being able to do this means that you have a lot of control over how much of a grid each image covers when it tiles, rather than simply assuming that an image will fill one square.

You will need them as tiles if you want them to be available for wall fills or to fill an area that you draw quickly.

Also, is there a way for me to enlarge tiles?

The tiles I made are one inch, but the DF tiles are 1/9 of that in size.

Tiles, by definition, will fill one square on the grid - though you can change the scale of the grid as you wish.
So, if you have a bigger image that you want to cover more squares of the grid, you have to set that in the tile info.
You can make the image 9x bigger (by area) by setting the tileinfo to 3x3; or if you want it 9x bigger by dimension, you would set it to 9x9.

Objects, of course, can be individually zoomed as desired.