Most desktop applications used under linux are able to display thumbnails of images stored on your PC.
To quicken the display of these images, Linux tend to store them. The problem with these thumbnails is that after sometimes, it occupies a large space causing memory constraint.
Below is a simple method of how to automatically clean up accumulated thumbnails.
Create file /etc/crond.daily/clean_thumbnails: sudo gedit /etc/cron.daily/clean_thumbnails
Paste in :
nice find /home/yourlogin/.thumbnails -name "*.png" -mtime +15 | xargs rm -f
(Do not forget to replace yourlogin by your login.)
Change status to executable file: chmod +x /etc/cron.daily/clean_thumbnails
Now all thumbnails having a lifetime of more than 15 days will automatically be clean up.