It looks like you're looking for the official Chrome OS Recovery image for the board (which is the Pixelbook 2017 ).
Usually every 4-6 weeks with the Stable Channel release. However, the recovery image lags behind the over-the-air updates. You will always receive the most stable, fully tested build. Chrome Os Download Recovery Image -rammus-
: "Rammus" is highly recommended because it supports a massive array of Intel processors, from 4th-generation chips up to much newer generations. rammus It looks like you're looking for the