Trying to use css to insert png icons in tag boxes

I was already trying that but with what I am trying to do I would need to try and convert like 400+ png icons to svg and then make all of that an svg sprite and from what iv tried and read there isn’t a fast or good way of converting them and keeping the quality of the original png. I did try with one icon a few times but the quality would usually go down and then when I put it into a sprite I couldn’t get it to load with the theme component.