There's some more older stuff on their website [2]; the test images from 2020 were a whopping 31694x31646. They have interactive zoomable images for those here [3].
[1] https://twitter.com/VRubinObs/status/1577050134218694656
[2] https://gallery.lsst.org/bp/#/folder/2334394/
[3] https://www.slac.stanford.edu/~tonyj/osd/public/