OSM is database, not a website and it does not store pictures, only links to them. ^1^

The most well supported way would be to upload the images to wikimedia commons, create a category for each spot there, and than add the category name to the wikimedia_commons tag on the element in osm.

• Tag documentation: https://wiki.openstreetmap.org/wiki/Key:wikimedia_commons
• General info on Wikimedia Commons connection: https://wiki.openstreetmap.org/wiki/Wikimedia_Commons

Renderer support:

• OsmAnd can display these images, in the section "Online photos" in the detailed view of an element
• Organic Maps adds a Wikimedia Commons button, which opens the category in the webbrowser
• On openstreetmap.org these links are clickable.
• Wiki lists some more renderers supporting this tag: https://wiki.openstreetmap.org/wiki/Key:wikimedia_commons#Support

Another common tag for this is the image tag, you can just link there a single image. https://wiki.openstreetmap.org/wiki/Key:image

Mapillary is a google streetview alternative owned by Meta/Facebook. It has it's own tag and you can link there images uploaded to mapillary. Note: this platform is not fully GDPR compliant, and owned by a terrible company, so I personally don't recommend contributing there, just it's a common option. https://wiki.openstreetmap.org/wiki/Key:mapillary

^1^: Except those strange guys who store base64 encoded images in the image tag, taginfo link, but it should be only really low resolution as there is an 255 character limit for values. I haven't found a renderer which could display this.