I've been contributing to Google Maps for a while, specifically, I usually upload pictures of menu's from restaurants, so future visitors can see them before they decide to eat there! I'm trying to degoogle my life a bit & was wondering if there is a way I could contribute these to OSM?
I've also wondered this. I'd also like to contribute info on how busy places generally are around me, so you know to show up early if you want a table, or don't bother dining in on a weekend, etc.
Apparently MapComplete integrated mangrove.reviews, and you can upload pictures from MapComplete, so that may be the best option for now?
Not specifically for restaurant menus, but more generally if you’d like to contribute to Open Street Map while out and about, depending on your area there may not be complete information for a lot of businesses. You can use an app like Go Map!! on iOS or Street Complete on Android (or many other OSM apps) to add information like business hours, website, phone number, and other useful information.
For photos, Wikimedia Commons seems like the best approach, although really any website will do (as long as there are no licensing issues w/ that site and OSM). There is a whole wiki page about linking OSM features to photos.