Restrict wikimedia_commons URLs as image=* tag values?

Sure. I will make changes only in Italy.

I’ve already converted about 3000 keys of images created by me (excluding guidepost).

There are still about 500 in Italy, but unfortunately, some of them are unsolvable. There are cases where both the image and wikimedia_commons keys are already present and point to different URLs. Typically, the image points to a File, and wikimedia_commons points to a Category.

For example: Node: ‪Orimento‬ (‪728285746‬) | OpenStreetMap

Besides guidepost, this is an additional inconsistency that we will have to accept.