Content Url Is Not Working In Firefox

My CSS file is: #name_wrong_img { width:43px; height:29px; } This is my HTML code: content property in the same way as Chrome — on img elements and/or when the source is an image.

<img> represents a content image. If you use it, it should have a src and an alt.

From the specification:

The src attribute must be present, and must contain a valid non-empty URL potentially surrounded by spaces referencing a non-interactive, optionally animated, image resource that is neither paged nor scripted.