This technique, known as LQIP (Low-Quality Image Preview), is used to improve the user experience by loading images in a non-ideal situation without losing the user's attention. It involves embedding small thumbnails of images as CSS backgrounds, which are then gradually replaced with full-sized images when available. This technique was initially introduced in 2013 but has gained popularity recently due to its effectiveness in reducing page load times and improving user engagement. Facebook has taken this technique a step further by using the same file header for all images and only sending the actual image data, resulting in smaller preview sizes. The technique is also known as SQIP (Shape-Quipped Image Preview) when combined with SVG shapes to generate vectorized primitive versions of images. This approach offers a unique, modernist preview style while achieving file size and compression possibilities that are close to the original LQIP technique.