If you’re having issues getting your Aperture images to show up correctly on your iDevice, there are two possible issues at play. Either the previews aren’t updating correctly as you adjust your photos, and/or the XML database that iLife relies on isn’t updating correctly. It’s less time consuming to reset the second, so here are the two things to try, in order.

Reset the Sharing XML database

Sometimes the databse itself gets messy and just needs to be rebuilt from scratch.

1. Plug in your iDevice and launch iTunes
2. In iTunes, under the Photos tab, disable sync from Aperture. Apply this to your iDevice (it will ask to delete photos; say yes)
3. Launch Aperture and open the Prefences
4. Go to Previews, and change Share previews with iLife and iWork to “never”.
5. Quit and re-launch Aperture.
6. Open the preferences again, and change that Share… setting back to “when quitting”, then quit Aperture (you can set it to “always” later on if you prefer)
7. Open iTunes, and turn Photos syncing back on from Aperture, and select the projects/albums/smart albums that you want to sync
8. Sycn and see if the problem is gone!

Rebuilding the Previews

Sometimes the previews don’t update as they are supposed to, and it’s easy to just throw them away and start over. If you have previes generation turned on for your entire library, this could take some time, so plan on letting it churn overnight.

1. In Aperture, go to the Photos view in the Library tab. This shows ALL the photos in your entire Aperture library.
2. Select all images, and choose menu Photos > Delete Previews
3. If you want previews for all images, then once it’s done deleting, choose Photos > Generate Previews. Again, this could take a long time.

If you don’t want to do this for the entire library, you can manage previews on a project-by-project basis. To learn how to do that, read this article, “A Comprehensive Look at Thumbnails, Previews, and More in Aperture 3”.