Using the tool compose.py, wont recognize the offeset fields for sprites that have the same dimensions as the tileset default.
Cataclysm-DDA\tools\gfx_toolstile_info.json the creatures.png sprite sheet has no offset defined in the script geneated tile_config.json file.Offset field is respected
At first glance it looks like intended behavior and is specifically defined in the code. What's the use case of having offset for default-sized tiles?
The offset helps reinforce the illusion of visual depth within the set. especially when character/monster sprites are offset. As, the tileset is curently trying, but failing, to do
I may be able to help with that a bit later. Can you meanwhile please add a screenshot to demo what result you want compared to what you get with current version?
Sure thing.
This is what I have.

vs the offset I'd like

so it looks like removing the explicit check for standard() should do what you want.
if I could just get vips to work on one of my machines I would be able to test that.