Generally, when the opacity is added to any div, it automatically adds opacity to all associated elements in the same div.
Get Css Transition Background Image Opacity
Gif. I made a small example without image sprites just to make clear what result we expect from a background transition with :hover for example. Your desired transition is implied by changing.
Css Transitions Module Level 3 from www.w3.org
Imagine you have three photoshop elements within a folder, as shown in the screenshot below: It works, but it's ugly. Learn to easily create css transparent background property in your projects.
It works, but it's ugly.
Your desired transition is implied by changing. And a transition happens when a property is changed. With css and css3 you can do a lot of things, but setting an opacity on a css background is not one of them. I made a small example without image sprites just to make clear what result we expect from a background transition with :hover for example.
