We work with a number of clients that are using SharePoint to stored scanned images  of documents either as multi-page TIFF or PDF format files. My only caution is that the Picture library  defaults are best suited to working  with JPEG files. This may be fine for your application. If you are planning a document  imaging type application then I would recommend storing the images in a standard  document library. In fact, I would recommend storing scanned documents in the same library as similar electronic documents if that makes sense. The only real issue we have encoutered working with multipage TIFF files  in SharePoint is that certain IE plugins try to register as the default viewer for TIFF images even though they can not display multipage TIFF images. By default, IE will open the images using Windows Picture and Fax viewer which works well for most people.

There are some hard-coded limits in SharePoint. for example, if an object has
over 500 MB of information - regardless of whether that object is a folder, doc
lib, site or site collection, you'll not be able to rename that object. For the
most part, this won't be a problem, but you should be aware of these
limitations.