I have a plentiful collection of music magazines, which contain many wonderful things inside them. One such item are adverts for upcoming album releases, however I’ve never found a really good place for these to be documented.
I would propose adding the advert to the first release in the country to which the advert was published, as a type of other, and then a comment explaining it?
Unfortunately I don’t think this is a ‘correct’ use of release images… I would love for this kind of thing to be supported by MB more directly. Maybe we could make a ticket for allowing release group images via the Cover Art Archive? And then artist images for other stuff, merch, etc. Would be amazing.
In the meantime I think feel free to upload the images however you think is best. I don’t think any of it will be ‘correct’ but that stuff is great to store and there’s no other way to do it.
I agree with @aerozol - it is great to see related stuff like that. Maybe include the date of the magazine? Then it has an excuse to be there as reference material to the release date.
But be prepared for a boring database person to come along and delete them as “Not relevant”. I’ve had boxshots removed before by editors