Here are a few photos of the faded sorta-Mediterranean mural at the NW 18th & Burnside McDonalds, next to the drive-thru. A mention of it in Sybilla Avery Cook's Walking Portland indicates it's been there since at least 1998. A 1991 Oregonian article refers to a mural at a McDonalds on W. Burnside, and this is the only McDonalds I know of on W. Burnside. So assuming it's the same store, and the same mural, this was painted by Mark Bennett, who's best known for creating the gigantic blue heron mural that towers over Oaks Bottom in Sellwood. A CNN interview with Bennett mentions that he's been creating murals since 1984, so it's newer than that; the "Open 24/7" part of the mural looks like it was maybe part of the "Mac Tonight" ad campaign that ran 1986-90. It's entirely possible it hasn't been repainted since then. I suppose it could use a touch up, but I actually kind of like the faded look in this case.