A quick Google search indicates that inkjet photo paper could possibly damage a laser printer. Laser printers use heat to fuse color into the paper. Inkjets spray ink onto the top of the paper. Two different systems, different coatings on the paper, etc.
While I think the worst that would happen with laser photo paper in an inkjet printer is that the ink wouldn't stick properly, the worst that could happen with inkjet photo paper in a laser printer is melted coating on components of the laser print head.
