Each image is given a unique id number in the system that is used to identify it to the various sub-parts. This row contains various information such as size, exif info, filename, description, subject info, plus some meta data. The actual columns in the table cant be listed here as there are too many. Meta data stored includes the number of albums that refer to the image, an md5 sum of the image to detect accidental duplicates, and image ratings. There is no relation between the information of any two images.
Albums are a little more complicated than the photos.
The system user who owns the album. There are two types of 'albums'. This basically is a page that lists more albums or more album lists. The second is an actual album of images. The major limitation at the moment is that you cannot create children albums from an album of images.