Save images to database or folder?

Well that depends on how and what your hosting plan would allow. If you're having both to be unlimited on size, then there is no trouble. However in most cases the File system (hard disk space for files) is provided as unlimited but database space is bound to be >500MB and <2GB. So it is of no use to store that much files in the database.

However, I would really suggest that you save the images and other files in the file system, not in the database. In the file system, you get more options to work with files. However, you can still convert the binary files you are having in the database but that is a long method of conversion to an object of File and so on.

So, in every aspect, saving the file in the file system is a better option (In my opinion).

Adding to the above answers, refer my answer - Where do you store image in asp.net[^].

I would suggest you save the file in the file system but the actual path in DB with related fields. So that you can retrieve all the info faster and only when user chooses to, download the file.