Picrew Maker Maleterms Of Use

You may only use the images generated from the image makers within the scope permitted by the creator and picrew. Please read and agree to the following statements before use. A creator may select his/her preferred permission scope from the following choices. You may only use the images generated from the image makers within the scope permitted by the creator and picrew. “user (s)” means, collectively, persons who use the service, regardless of whether they have registered as a member.

It depends on what you mean by use. If it's for anything for profit, you should always reach out to them and ask for permission. But if it's just for fun or pfps, i think credit is enough. It depends on which picrew maker you're using, since creators can pick and choose the 4 permissions to their liking. I'd say making ocs falls under personal use and mascot depends.