Why do some websites duplicate their background images, to fill the screen size, rather than upload a larger image in the first place? : <p>For the past few days, I have been looking at the various ways websites upload background images to their website via CSS.</p>

<p>When it comes to images which can be duplicated endlessly, such as plain stripes, I have noticed that some websites upload a small 'sample' of the image and then duplicate it with a CSS input such as <code>background-repeat: repeat-x;</code> rather than uploading a larger version which scales according to screen size.</p>

<p>Is this, primarily, a page load speed optimisation exercise, or is there another reason why somebody may wish to do this other than due to the original image being small in the first place?</p>
