I have a gif image. It gets shown only on very specific events, not too often. By default, the gif\'s html tag is hidden using
display: none
If you are hiding any imges(s) / iframe(s) through css's display:none or you are hiding any div (or other tag) through this css rule (display:none), image(s) / iframe(s) etc within this tag will not be loaded in the browser. It means browser will not make http request for these elements.
Browser will sent the request to the server after you change the display property to other then none.
It is not about img, but all the resources which makes server requests.