2002.02.13 14:31 "Re: Multi-page TIFF; how does it work?", by Martí Maria
Your question is not so obvious. The short response would be, each image in a multi-image TIFF is stored in a separated directory. So, check the number of directories and you will get the number of images.
However, there are images on that this doesn't apply, since they are Pyramidal TIFF and each directory does store a copy of same image at different resolution. There could be also subdirectories containig thumbnails, alpha masks and other goodies. In this case, the question is if these are or not to be taken as different images.
In general, check the NewSubfileType tag to see if the directory contains a reduced resolution copy (bit 0) or a alpha mask (bit2). This works on most cases.
Hope this helps,