Tip: Reduce Thumbnail File Sizes in Aperture 3

Just a quick tip on how to reduce your Thumbnails folder in Aperture 3 with around 50%, if you’ve been running Aperture 3 since it was first released. The latest update (3.0.2) fixed an issue with thumbnails being larger in filesize than actually needed and I concur – my thumbnails folder was almost 9GB for just 10,000 photos, almost 1MB per thumbnail – that’s some hefty thumbnails, don’t ya think?

What I first tried – which didn’t work for me – was to simply select all photos (CMD+A) and go up in the Photos menu and select Generate Thumbnails. It took probably around an hour or so, to run through all photos and generate thumbnails – but to no avail, my thumbnails folder was still at 9GB. Next, I tried to hold down ALT+CMD when launching Aperture 3 and rebuilding database, repairing etc. Nothing.

Then I thought, why not simply drag the thumbnails folder from within the Aperture Library package, out to my desktop? I did that (after having made a backup of my entire Aperture Library package, all 45GB of it). Next time I launched Aperture 3, it started to generate thumbnails from scratch. After a while it was finished and voila, my thumbnails folder was down to less than 5GB. I’ve even seen people reduce their thumbnails folder with 50%, so this is definitely worth doing if you have a lot of pictures and if you’ve been running Aperture 3 from before update 3.0.2 was released.

To check the size of your thumbnails folder and compare it to how many photos you have, go to your Pictures folder on your Mac hard drive. You’ll find your Aperture library there, most likely named such. Right click it and select Show Package Content. Now you can simply CMD+I on the Thumbnails folder and get all the information you need.

You might also want to read this article on how to speed up your Aperture 3 in general, if you’re suffering from a very sluggish application, especially when doing adjustments: Aperture 3 Performance Fix – Make Slow Aperture Run Faster.