A work around is delete them using your file explorer. Navigate to your assets folder and delete the ones that are not used. If only some assets are compiled, that means those assets are being used somewhere in the SDS project. SDS also has a Project Settings called “Force export all images” which will compile all assets, even the ones not used.
I solved the problem by manually deleting the files. But I confess that this is not intuitive.
I thought that by placing the files there, I could delete them by clicking and pressing DELETE
If the software does not yet have this feature, this is an honest suggestion. And not as a criticism, your software is incredible!! And I love squareline studio