Problem with referencing small images on the page_html/css_WEB-ITnose

I often see a large number of 1*1piexls sized pictures on some portal websites. What is the main function of such pictures?

If there are multiple 1*1piexls images on a certain page, that is, there are multiple HTTP requests, is it feasible to modify them all to reference the same 1*1piexls image?

Reply to discussion (solution)

Used as background image

But 1*1piexls The picture cannot be seen on the page at all

But the picture of 1*1piexls cannot be seen on the page at all

It can be seen after tiling

One page Are the multiple 1*1piexls images used as background images? So why not use one?

It saves space, and if the page is large, you only need to tile multiple pages without cropping the size

Oh, I understand, thank you both;