Any kind of website that has a member login system will need a database.
As for your specific example, what I’ve seen done more is to store the image *path* in the database but store the images in a folder on your server that the database simply references. But I’ve only worked with databases on very large sites where saving the image in the actual database was not practical, so others might do this differently.
And you shouldn’t be afraid to ask questions of your professors – otherwise what’s the point of going to school? It’s probably that more than one person has the same question as you. :)