I need to set the image `height` everytime I'm using `background: url('images/something.jpg')[..];`

Fe. 

HTML:

```
<div class="someImage"></div>

```

CSS:

```
.someImage {
    background: url('images/something.jpg') no-repeat top;
}

```

The above example should work... but image won't display until I add an image `height` attribute to the CSS style class:

```
.someImage {
    background: url('images/something.jpg') no-repeat top;
    height: 25px;
}

```

And then my image appear on the website...

Why does it happend?