Where to use png sprites?

Question

css

Sprites need to replace icons of the same type, or in general, everything you want? For example, in my layout I have various arrows and other icons 17x17 in size, I throw them in 1 sprite, but there are also pictures, for example 40x40, can I put them in a sprite too, is this considered good form?)
And more the question is, there are elements on the page that are usually done through img, is it normal to make a span and give it a sprite of this image as a background?

Answer 1

1) One sprite can contain any cards of any size.
2) Well, this is not the norm, it’s normal for icons to do this, and it’s better to give some kind of icon class, and hang the icon itself with a background on before or after