How to apply specific styles to an image with transparency?

Question

css

The task is simple, determine that the image has transparent pixels and remove the border from it.
I decided to illustrate with code:

img {border: solid 1px red}

img искомый мистический селектор  {border: none}

Answer 1

css has no idea if the image has transparency. You can of course catch on to the file extension, but png and gif do not guarantee transparency. and talk about its possibilities. Is it only about jpg that it can be argued that it is not there.
I think you are solving the problem in the wrong way. This should be done in js.