In System Preferences → Desktop & Screen Saver, it's possible to set an interval for changing the desktop wallpaper picture:
However, you are limited to a few specific times:
Is it possible to set a custom time for this interval?
I found this Apple scripts web page with examples.
There is a line in this script for the change of interval time allowing you to specify it, and you can customize the rest of the script to your needs.
tell application "System Events" -- RANDOM ROTATION OF A FOLDER OF IMAGES tell current desktop set picture rotation to 1 -- (0=off, 1=interval, 2=login, 3=sleep) set random order to true set pictures folder to file "Mac OS X:Library:Desktop Pictures:Plants:" set change interval to 5.0 -- seconds end tell end tell