I will confirm that I had a major problem with syncing my photos. It gave me the error that "disk could not be read/write." I re-set my iphone to default settings, reinstalled ios into iphone, no luck. I re-built the iPhoto database, thumbnails, everything, no luck. I then deleted the iPod Photo Cache and it worked! To find the correct files to delete, you have to:
1) right click on iPhoto Library (located in your Pictures) and select "show package contents"
2) new window will pop up and you will see the "iPod Photo Cache" which select it and delete it.
3) sync iphone again and it will rebuild the photos for your iphone and it works great!
I'm on iTunes 10, iPhoto '11 (version 9.1) and iPhone 4 (IOS 4.1)
You may want to go to iTunes and select "Sync all Photos" and note the number of photos that appears in the upper right of the window, so you can make sure that it's higher after this process.
Originally Posted by EG6