'... sorry if its an odd question, I am new to os x ...', no problem. There are Mac'ers with up to 18 years of real Macintosh experiences (System 1.0 - 9.2.2) that share your MacOS X (10.0.0 - 10.4.2) confusion and frustrations.
01. Basically, one is never ever to place a file or folder of items - into the folders of the '/System/Library/' folder (accessible via 'root' or overridden by an administrator). Such folders are reserved for Apple Computer, Inc.; including the '/System/Library/Screen Savers/' folder.
02. For all users of your Mac to have available a screen saver, place the screen saver file into the '/Library/Screen Savers/' folder (accessible by an administrator).
03. For only a current user to have available a screen saver, place the screen saver file into the '~/Library/Screen Savers/' folder. Where '~/' is the current user's 'Home' folder (accessible by the current user).
'... The weird thing is no matter where I put those screen savers, they show up on both accounts.', I am assuming you mean either the '/System/Library/Screen Savers/' and '/Library/Screen Savers/' folders. If so, yes - you are correct.
All applications in the '/Applications/' and '/Applications/Utilities/' folders are accessible by all users of the Mac.
The notes of 02. and 03 above applies to 'Widgets' as well. Thus, installing a widget into the '/Library/Widgets/' folder (accessible by an administrator), makes it available for all users of the Mac.
Installing a widget into the '~/Library/Widgets/' folder (accessible by the current user), makes it available only for the current user. If the '~/Library/Widgets/' does not exist, one can create it.
With respect to 'Desktop' pictures, Apple allows each user of the Mac, via the 'System Preferences' 'Desktop & Screen Saver's 'Desktop' tab's left side column - to select 'Choose Folder...'. From the selections resultant drop down sheet, one can navigate to a folder and select a graphic file - to be the 'Desktop's background image, for that current user. Thus, each user of the Mac can have a different 'Desktop' background.