Almost any website with an image gallery is a better source than Instagram for browsing images available on both even for those with Instagram accounts; the image quality is almost always better elsewhere.
There are also pretty active facebook groups where she and others post remarkable slime mold photos ("Slime Mold Identification & Appreciation" and "Ascomycetes of the world").
https://linktr.ee/AlisonPollack
Ironically, iNaturalist is the better source than instagram for browsing her pictures (at least if you don't want to open an account).
https://www.inaturalist.org/observations?user_id=alison_poll...
https://www.instagram.com/marin_mushrooms/