What is the license?
MIT is for code... Art usually uses CC licenses https://creativecommons.org/about/cclicenses/
Take a look on them...
For MIT license user must save text of MIT somewhere so in this case it is crediting...
Ok. But i still have a question. Don't you need credits? Or you just decided to use CC BY that requires credits
Anyway, you should add the license into metadata for the asset pack(s):
"Edit asset pack->Metadata->Release Info->License for assets" It will increase the size of audience that will be able to find your art