Spatial DB lookup to image DB

I am working on a library project for rectifying old map imaging on a map. The images are in tiff and jpeg formats.

After rectifying the images I want to save the geographical information in a PostGIS database, while the image itself will remain in another DB, in the same format.

What methods I can use to query the images DB with geographic data based query? (i.e. polygon search on the map will retrieve all rectified maps on that area)