Thanks for the answers so far! I find it interesting to hear others viewpoints on this, especially those of you who do model things.
I understand not all modelers take images from google or buy images without even reading the license first, but it does seem to be a common practice by many who don't understand copyright or licensing.
I've been looking through this site to find some nice different types of home decorations to use in my projects, but keep coming across items with artworks which I'm unsure of who made and if whoever made it actually approved the use in 3d objects for sale. Like for example, framed paintings, books (often real world books with real world book covers), real world cosmetic brands with their logo and brand name on them etc.
I come across these so much that I sometimes think, maybe they got a sponsorship deal with a brand to make their products into 3d models or something, who knows.
If I will use these in my own commercial projects, I will want to be sure of that I myself aren't violating any copyrights, which becomes a problem if the texture (or brand/logo contained therein) is owned by someone else.
At the same time, I also have found models that, instead of simply copying the exact real world item and selling it, they make up a whole new "pretend" brand, which I think is nice to see. Like I recently found a set of soda cans with made up names and artwork for example.