How can I exclude the display of specific pictures and videos in the Finder?
I am unsure if you are asking how to exclude folders from showing up in your finder spotlight search, or if what you are after is to hide specific folders from being shown in a finder window.

If you are after excluding folders from a spotlight search, you can do this in the privacy tab from system preferences / spotlight :



If you are after having the ability to show or hide files and folders from being viewed while you are in a finder window, then you can create an automator service to do just that :

hints.macworld.com/article.php?story=20100719001040829

NOTE : the tip above only toggles all files that have the hidden flag set, so if you need to quickly mark a folder or a file as "hidden", then you need to set this bit attribute for that file or folder.

An easy way to do this is via a free utility software download that does just this here (used to be shareware, but now free ) : gotoes.org/ShowHiddenFilesMacOSX/

NOTE 2 :

If you are happy using the terminal command line, you can just type the following on the terminal :

chflags hidden (drag your file or folder onto the terminal window here)


or

chflags nohidden (drag your file or folder here)


Hope this helps.