What this has anything to do with raster and vector graphics and how exactly can u tell that the wallpapers we use are of the same size? An image with rich graphics and more details will weigh more in size than a blank image with no graphics both having the same dimensions. A 1x1 pixels image used as titled on your desktop background is going to have a 500 times less size than a 1024x768 image with graphics and details. I cannot question the suggestion given by OP. When we use a desktop wallpaper it uses our system memory and yes its not a good idea to use an animated background if your RAM is even 256k. AND trust me it has NOTHING to do with pixels but the size of image that will eat your memory.

the raster graphics is concerned with wallpaper or the display image on your monitor screen, and it does relate to "pixels". raster graphics image is a data structure that represent grid of pixels_so pixels are involved when we talk about wallpapers or background images_
you are correct that heavy images weigh more than a simple image "BUT" the computer knows how to deal with such issues and it can handle the RAM usage too.it actually "REDUCES THE IMAGE SIZE" by"DATA COMPRESSION TECHNIQUES".

and you cant separate the image and pixels. it has to do alot with pixels. pixels are everything that make you see your background images. infact the resolution of your screen and the amount of information in each pixel ( the color depth) determine the raster image quality.
the standard for display is 24bits/pixel since 1995. it depends on the internal architecture of your system how to handle the graphics. if it allows 24bits/pixel then it can manage its usage also, and if it allows 16 bits/pixel then it manages so. and internal architecture oes bring into account the efficient usage of RAM too.

nowadays almost everyone is using windows XP and they can use XP only if the prerequisites or space requirements are fulfilled.xp and other advanced windows IS BASICALLY DESIGNED TO GIVE HIGH PERFORMANCE TO THE USERS. it wouldn't be wise in anyway to consider a heavy background as a factor affecting the performance of a system, coz there are hundreds of other issues
on which research work is being done to increase efficiency and performance.the "BENCHMARKS" used to test the performance of a particular architecture never brought into account the issue of heavy backgrounds, rather to satisfy performance requirements other issues are considered such as the techniques of asynchronous I/O, optimized protocols for networks( eg optimistic locking of distributed data, batching of requests),
"KERNEL-BASED GRAPHICS", and sophisticated caching of file system data.THE MEMORY MANAGEMENT AND SYNCHRONIZATION OF ALGORITHMS ARE DESIGNED WITH AN AWARENESS OF PERFORMANCE ONSIDERATIONS RELATED TO CACHE-LINES AND MULTIPROCESSORS.
windows XP uses dozens of other improvements such as reducing code-path length in critical functions, using better algorithms and per processor datastructures.the subsystems (including win32 ENVIRONMENT that handles screen I/O, images etc) that constitute Windows XP communicate with one another efficiently by local procedure calls facility that provides high performance message passing and hence increasing performance.
failure of any of these functionalities or subsystems WILL cause system failure or reduce its performance

the usage of 64MB RAM is obsolete nowadays and surely its good for nothing, regarding todays technology.

I wasn't expecting you to copy and paste your final year thesis to debate on the point you were trying to make but still clueless.. And i know what vector and raster graphics are; as graphic design is my profession. I was referring to pixels and i said it has nothing to do with system memory. Its the size of image we are talking about here. You get a 1x1 pixel image and use it as a tiled background to cover your entire screen having 1600x1024 resolution all filled with pixels of the same image. The image may weigh less than 64 bytes and in other words using 0.00% of your system memory but at the same time u take an image of say 1.5MB size having 1600x1024 dimensions with rich graphics and use it as a background on a system with 128-256mb RAM and compare the performance. I will not worry here because i have 4gigs of Ram and thats what i need for my graphic design work but an average user having a 128-256 ram will experience low performance and poor startup.

The suggestions posted by OP was to help an average user optimize the performance and i totally agree with them.

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