Is it the picture's ink, paper, or a combination of both?

I usually get my pictures printed Glossy at Walgreens & have no problems.

Today I got a picture back that was printed matte at Walmart (I'd argue that they don't know the meaning of the word matte, as I'd definitely call it glossy, but that's another issue) and the Sharpie comes off just as it would if I printed it at home.


I always understood the Metallic Sharpie issue to be the result of the "metallic" aspect of the Sharpie containing something that didn't jive with amateur photo printer inks, and my experience with Walgreens essentially confirmed that belief, as I've never had a single problem, even on the glossy paper.

Have I misunderstood the issue or is Walmart just using amateur quality materials?