Png animation or .gif?

Question

css

What is the best way to set background animation for div via img with z-index or image in background-url?
And which format is better .gif or .png?
Why?

Answer 1

What is the best way to set background animation for div via img with z-index or image in background-url?

It’s not better at all, different solutions are suitable for different cases, for example, z-index is sometimes more convenient for dynamically changing content, and for static content it’s more convenient to write a background in css. Although both options have their advantages and disadvantages.

And which format is better .gif or .png?

gif lost its relevance a long time ago, now under the guise of a gif, mp4 animation is usually shown. GIF (mp4) or png should be selected individually for the picture in each case, since for example a picture with a small number of colors in the palette is better to compress in png, and live video in mp4.