My ipad appears to have hit a brick wall for adding images. It has been sitting 'syncing my ipod' for several hours. If I do a talley of the files in the iPod Photo Cache I get this : 24,615 items, totalling 8.5 GB. (Per my earlier comments, that is actually about 4GB of jpg). It made it to 124 photo albums before locking up. It clocks on any attempt to adjust or remove albums. If I want my ipad to ever sync again I will likely have to start fresh with a new sync-image directory.
There appears to be an upper threshold to the total number of images the ipad can handle and it is way under the 60GB potential of the device. From what I've read, it has to do with the amount of thumbnails the OS can keep in its 256MB memory.
So... in other words, do not expect to be able to put more than 4GB of photos on an ipad.
The image capabilities of this device have been a series of disappointments. From a usable space perspective I have went from 60GB to 30GB (space consumed by the ipad = 2x jpg space) to a whopping 4GB of jpgs (memory limitations). And then there are all the flaming hoops I've jumped through to get the sorting of albums and images to be correct. Very lame.
I can try other routes (media stash) but I love the look of the built in photo viewer and wanted desperately for that to work. I guess I was asking for too much. If it didn't take so damn long to load images onto the device I'd find this limit workable. As it is, every time I want to work with a set of albums I will need to wipe the preceding set and load the new set, which will likely take 1/2 to a full day.
This discussion thread goes a bit into it:
Apple - Support - Discussions - Is there a maximum number of pics that ...