This is a book louse (psocid), submitted for ID in the forums. Many bedbuggers have mistaken book lice for bed bug nymphs. Notice the shape of the body is elongated, with three clear segments. There’s a pronounced head.
Compare this photo from L. Sorkin and R. Mercurio of a bed bug nymph:
Both book lice and bed bug nymphs are light colored but bed bug nymphs have a less elongated body. Bed bug nymphs don’t look like they have a neck, whereas book lice do. Bed bug nymphs are clear but will become red when they have fed.
If you find a book louse, don’t worry — they are common in homes and don’t usually pose a problem. Despite the “louse” in the name, they don’t have anything to do with species that feed on humans. If you want to learn more about psocids including book lice, here’s a fact sheet from the University of Minnesota: Psocids in Homes, by Jeffrey Hahn and Steven Kells.
Many thanks to the user who shared the book louse photo, and gave us permission to use it here.