The Miniature Book Collection is by the University of North Texas. The digital collection consists of 150 objects from their physical collection of nearly 3,000. They have information listed about the collection development policy for their physical collection of Miniature Books, but I could find none for this digital collection, with a lack of information in general about their decision-making processes. For this reason, it's hard to tell who the intended audience for this digital collection is, as well as its scope and purpose.
It looks like these may be photos rather than scans [edit: or maybe a book scanner, here's an example], with most of the preview pictures at 96ppi, and a few at 72ppi. There's a lack of uniformity to the resolution of the magnified images, with some at 72ppi, while others are as high as 800ppi. The same lack of uniformity applies to what parts of the books are digitized, and on close inspection it appears that decisions were made unique to each series in the collection (I'm inferring, because I could find no information about their decisions).
For the Art Press series, there are pictures of all the pages in the books, with resolutions of 96ppi for the preview pictures, and 72ppi for the larger pictures. For the Weaver Collection of Children's Books series, there are pictures of all the pages in the books, with resolutions of 96ppi for the preview pictures, and 800ppi for the larger pictures. The Mijn Bibliotheek series only has pictures of the front and back covers, 96ppi for previews, and 400ppi for larger pictures. There's a nearly complete series of Tiffany & Company calendars from 1907-1942, with pictures of only the front cover, 96ppi previews, and larger pictures ranging in resolution from 400-800ppi.
The metadata also varies by series, with the Art Press series, and books donated by Robert E. Massmann containing extensive copyright holder information that isn't available in many of the other series. In all cases however, the labeling is clear, with information to facilitate ease in finding the physical object. Most also have detailed physical descriptions, with extensive information on edition size, background, and purchases/donations.