I found out the cause.
To solve it, go to System Preferences > General and put a check mark next to "Close windows when quitting an application"
Should do the trick
When I double-click a Preview file icon on my desktop many files are automatically launched with the file I clicked appearing last. Can I set preferences so only the file I double-clicked appears? If so, how can I do that?
My iMac is 2.8 GHz Intel Core 2 Duo, using OS 10.8.3.