Is it possible to use this pack in GB studio? Or are the assets to big?
The assets have an estimated total size of 24.55 kb.
Most tiles are 8 x 8px in size, except for those with slightly more unusual shapes (crates, doors, coins, etc.) or backgrounds (clouds, foliage, etc.).
Personally, I cannot recommend it for GB Studio, as it may not meet some of the program's usage requirements and I may not be able to provide the necessary support, as I am not familiar with the program.
In any case, you can try it, but at your own risk.