Hi,
For images in OpenBenches just add the openbenches:id tag to the OSM element so that anyone can view the images directly on the project site.
I am an active contributor to Open Plaques, a project similar to OpenBenches. Like OpenBenches, Open Plaques has an openplaques:id tag that allows you to view the plaque images on the project website.
I usually use two tags, wikimedia_commons and openplaques:id. This way, people who want to view images can choose where they want to view them, either on Commons or on the project site.