It might be easier to use CSS to achieve a gradient background rather than an image.
For example, if you wanted to use a gradient background on all pages throughout the Kosel theme, you could add the following code to the 'showkase/_themes/kosel/css/custom.css' file:
body {
background: -webkit-linear-gradient(#ff0000, #0000ff); /* For Safari 5.1 to 6.0 */
background: -o-linear-gradient(#ff0000, #0000ff); /* For Opera 11.1 to 12.0 */
background: -moz-linear-gradient(#ff0000, #0000ff); /* For Firefox 3.6 to 15 */
background: linear-gradient(#ff0000, #0000ff); /* Standard syntax */
background-attachment: fixed;
background-repeat: no-repeat;
}
If you wanted the gradient background to be applied only to 'Basic' pages (for example), then you could replace:
... with:
You could also apply it to only a certain page by checking the page number in the class attribute of the <body> tag of the page in question and then using something like:
You can change the gradient parameters as necessary.Please see here for details.
More information about using the 'custom.css' files within Showkase can be found here.