Pics in OSX Snow Leopard

Hi Everyone! I am new to the mac scene. I just got my first macbook pro and i have a question in respect to pics i am finding when you double click on the Macintosh HD or in Finder it opens up and displays choices along the left side.

Under the header "SEARCH FOR" there's a choice for "All Images". I've got a ton of pics in there. Some are from ones that I never really saved but rather viewed while looking at emails. I was wondering if I delete them all to clear out that folder am I also permanently deleting them from my hard drive? Is this just a temp folder? I dont want some of those pics. Why would the pics be saved on my hardrive by me just viewing them? is this a temp folder? please advise if anyone has knowledge. Thanks in advance !

Anything under search for is on your computer...
You will notice that if you go into user/pictures folder and delete a picture, that it will no longer show up under search for, unless you have a copy of that picture in your iPhoto.

Yes you will delete them.

Those prebuilt searches are "Smart Folders"

A smart folder lets you do a search and save it as a folder. The contents of the folder is dynamic, meaning that as more images are added to the HD they are also added to the smart folder. Unlike a burn folder which only contains aliases to the items that are dragged into it, the smart folder is in essence a saved search so you are viewing the live items. You can also create smart folders in the Mac Mail app as well for searching email by certain criteria.

If you want to create a smart folder for just .jpg files or .tif files you could do that as well. Or files that contain image or img in the name.

You get the idea.

I would also have a squiz through this Apple - Find Out How - Mac Basics ....... not many do, but I thing it is well worth while.
Under the tutorial window you will find a vast array of topics!
Every now and then even though I've used macs for some time, I still like to run through them to remind myself of some of the features that I have forgotten due to not using them often.