An inventory of about 330 large format paintings also belonged to Johann Valentin Prehn’s universal collection. Around 100 of these works can be seen on the watercolored drawing by the painter Carl Morgenstern, a friend and neighbor of the Prehn family, created in 1829 on the occasion of the planned auction of the collection. The image shows closely cropped paintings covering the walls of a long, low-ceiling room like wallpaper. The works are hung symmetrically in Baroque fashion: a central axis is surrounded by associative counter pieces. Exploiting every available place, Prehn filled the in-between spaces with further small format works, and draped the half-height cabinets in the middle of the room with paintings as well.

According to the 1829 auction catalogue the collection consisted mainly of Dutch, Flemish and German paintings from the 17th and 18th centuries, as well as contemporary artists from the Frankfurt area. Older German paintings, or works by French and Italian artists, were by contrast rare. The thematic focus consisted mainly of landscape paintings, genre pieces, biblical histories, and portraits.

Most of the paintings were auctioned off in 1829 and are no longer traceable. Only 40 of the images came into the possession of the City of Frankfurt in 1865, largely due to a donation by Johanna Rosina Sänger, born Prehn.