How to make image hover in css?

Question

I want to change the image from normal to brighter when it's on hover, My code:

    <div class="nkhome">
        <a href="Home.html"><img src="Images/btnhome.png" /></a>
    </div>
.nkhome{
    margin-left:260px;
    top:170px;
    position:absolute;
    width:59px;
    height:59px;
}
.nkhome a img:hover {
    background:url(Images/btnhomeh.png);
    position:absolute;
    top:0px;
}

Why doesn't work the hover? When my mouse is on it, it shows the first image, not the hover image.

Answer 1

You've got an a tag containing an img tag. That's your normal state. You then add a background-image as your hover state, and it's appearing in the background of your a tag - behind the img tag.

You should probably create a CSS sprite and use background positions, but this should get you started:

<div>
    <a href="home.html"></a>
</div>

div a {
    width:  59px;
    height: 59px;
    display: block;
    background-image: url('images/btnhome.png');
}

div a:hover {
    background-image: url('images/btnhomeh.png);
}

This A List Apart Article from 2004 is still relevant, and will give you some background about sprites, and why it's a good idea to use them instead of two different images. It's a lot better written than anything I could explain to you.

Answer 2

Simply this, no extra div or JavaScript needed, just pure CSS (jsfiddle demo):

HTML

<a href="javascript:alert('Hello!')" class="changesImgOnHover">
    <img src="http://dummyimage.com/50x25/00f/ff0.png&text=Hello!" alt="Hello!">
</a>

CSS

.changesImgOnHover {
    display: inline-block; /* or just block */
    width: 50px;
    background: url('http://dummyimage.com/50x25/0f0/f00.png&text=Hello!') no-repeat;
}
.changesImgOnHover:hover img {
    visibility: hidden;
}