After a week of off and on fighting with the ipad to get images onto it I thought I'd provide some assistance.
I bought the ipad specific to view images and it has fought me tooth and nail. Apple is making this hard on purpose. They don't want you to be able to control your images organization. The information below will get you as close to control as you need.
Here are the rules of thumb you need to keep in mind:
1. You get one layer of folders/albums. This is obvious but it bears repeating. If you have lots of books of images keep in mind that volumes are better than chapters. Chapters will overwhelm you.
2. Albums are displayed in the order they were added. From that point forward, any image changes within an album will cause the album to move to the bottom. If you want to a new album to display prior to existing albums you need to do this:
a. add the new album (shows up at the bottom). Adjust one image in each album above it and they will move below it. This should be easy to do in a program. I have done it for a handful of albums by hand to prove it works.
3. Images sort by last modified date BUT that is not the only criteria. It will also sort by some mystical exif data. If you want your images in a specific order you must wipe all the exif data and set the last modified dates to match the alphabetical sort. I wrote a program to set the modified date. I think there is free code out there to do this somewhere.
4. The ipad likes to be finicky about images included. I've seen it drop anywhere from 1 to 30 images from 1 album. I am unsure if this is network or format related. To combat this I do 2 things:
a. pass them all through a format conversion process turning them into jpg. Even if they are already jpg I pass them thru.
b. load 1 album at a time and then check the image count.
I have an example below that uses imagemagick (mogrify) to reprocess my images. This works 99% of the time on image that would not otherwise load.
5. There is nothing you can do about image optimization. I've tried resizing them to fit 1024x768. No dice. They are still optimized. This means you must be a patient person because it is frick'n slow. I am still resizing them to fit within a bounding box of 1024 because this is where I will be viewing them.
If you have linux, this is the uber command to clean up images in directory:
mogrify -strip -resize '1024x1024' -format jpg *;rm *.png; rm *.PNG; rm *.gif; rm *.GIF; rm *.bmp; rm *.BMP
That command does 3 things for you:
1. gets rid of any pesky exif data that can screw up the sort
2. ensure the image is in a format the ipad likes
3. reduces the image size to hopefully speed up optimization a bit
The rm commands after the mogrify statement remove any original images after their conversion to jpg. otherwise you will be left with any original non-jpg images and the new jpg images.
This does not solve the image sorting issue. You need a script or program to set the last modified date to by in synch with the file name.
This should be all you need to get your images on the ipad under control. I hope it helps and saves you a ton of time and hair pulling.
EFFECTIVENESS OF MOGRIFY (imagemagick)
Using mogrify on images has worked on 10,000+ images except for one. Re-saving that image with the gimp (unix image editing tool) was not enough to get it to load. I renamed it and slightly cropped it. Then it took. I'm scratching my head at that a bit but overall mogrify does the trick.
FOLDER ORDER IS FINICKY
Folders do not always stay locked in position. 2 rules of thumb seem to apply:
1. renaming an image will not cause the folder to move
2. changing an image will cause the folder to move to the bottom. I think anytime a new photo is sync'd into a folder it is pushed to the bottom The ipad is "smart" enough to ignore name changes.
The capacity of the ipad in terms of images falls far short of its total capacity. This is a limit that I've learned the hard way. There are 2 issues here:
1. size of an image after it is processed by itunes. If you have a jpg that fits the size of the ipad (1024/768), expect the final image store by itunes to be 2x this size. This is because itunes stores 4 different versions/sizes of your image. This means that the true capacity of a 60GB ipad is 30GB for photos. But... you'll never reach that 30GB limit because of issue #2...
2. There is an upper limit to the number of images an ipad can manage in memory at once. I have found that the limit is about 4GB of jpgs (8GB used space on the ipad). In terms of images, I was able to load 24,615 images, totaling 8.5 GB space in the photo cache folder before itunes syncing would just sit forever. That was 124 albums.