Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

User profile for user: penguin_5
penguin_5 Author
User level: Level 1
0 points

Flushing thumbnails

After a fruitless Google search, where all the top results assured me that OS X and Finder +do not+ cache thumbnails for images to disk, I came here to ask the same question again:

Where do OS X or Finder cache thumbnails for images, which persist after a reboot and after deleting .DS_Store files?

The attached animation shows persistent thumbnails.
User uploaded file

Macbook, Mac OS X (10.6.4)

Posted on Jul 12, 2010 2:58 AM

Reply
4 replies
Sort By: 
User profile for user: Roger Wilmut1
Roger Wilmut1
User level: Level 10
131,392 points

Jul 12, 2010 3:20 AM in response to penguin_5

As far as I can see it doesn't cache them: it generates them each time. Experiment: open a folder which has a large number of photos in it. From the View menu choose 'Show view options': check 'Show icon preview'. Close the folder.

Each time you open the folder you will see the Finder working through the images adding the thumbnails, presumably by reading the contents of the file and generating the thumbnail from that. The .DS_Store file has nothing to do with thumbnails: it remembers the location of Finder windows so that they open in the same place the next time.
Reply
User profile for user: penguin_5
penguin_5 Author
User level: Level 1
0 points

Jul 14, 2010 8:24 AM in response to penguin_5

/var/

That's the answer. There are a lot of caches there, one of them is the QuickLook cache. On my computer it was larger than 200MB.

/var/folders/mT/mTquOe7NE5yGh9Ojy7eNnE +TI/-Caches-/com.apple.QuickLook.thumbnailcache $ ls -lh
total 548712
-rw------- 1 usr staff 0B 13 Oct 2009 exclusive
-rw-r--r-- 1 usr staff 12M 14 Jul 16:24 index.sqlite
-rw------- 1 usr staff 256M 14 Jul 17:42 thumbnails.data
-rw-r--r-- 1 usr staff 42K 14 Jul 06:24 thumbnails.fraghandler

Ridiculous. Finding this answer shouldn't have taken so long. Seems like everyone is content with the wrong answer that "thumbnails are cached in RAM"...
Reply

Flushing thumbnails

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple Account.
Learn more Sign up