Please forgive my necro... This seems like a perfect tool to import DEFAULT tiles into your CUSTOM tilesets.
However what I'd love to do would be to import CUSTOM tiles into DEFAULT or CUSTOM or NEW tilesets instead.
It seems like the only way to do this now would be to create a fake 'New Data' folder and place your custom tiles with default tile names... and even then you're limited to only the default tilesets amount.
To be honest this greatly diminishes the usefulness of such a great tool, and from the other comments in this thread I can see others struggled to do the same.
I wonder if there's an alternative (I mean, except painful manual photoshopping on a grid), or if
@taarna23 would care to build this feature?
I don't think it would be too hard to implement, considering the amount of great work you've already put into it.
Just to be clear, what I'd love is:
The left side of the tool to list ALL the tilesets and tiles that I have, default, custom, anything (provided they're in the right format) instead of just default MV tiles. Basically all that needs to be done is the ability to import extra tilesets for the 'Source Tileset' option.
This feature would really make it the most amazing tileset builder.