While creating a website that SHOULD be compatible with IE6, I was forced to find a solution to make Nivo-Slider also compatible with that damn old browser. Turns out it's not that difficult.
Step 1) Using an image editor (I used Paint.NET), split arrows.png in two separate images: the left half becomes arrow-prev.png and the right half becomes arrow-next.png. Original image is 62x34 pixels, so you'll end up with two images measuring 31x34 pixels each.
Step 2) Open nivo-slider-ie6.php file, find line # 159 (that's between </style> and <script type="text/javascript"> tags) and paste the code below:
<!--[if lt IE 7]>
<style type="text/css">
* html a.nivo-nextNav {
background: none;
filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src="<?php echo WP_PLUGIN_URL . "/wp-nivo-slider/"; ?>images/arrow-next.png", sizingMethod="crop");
}
* html a.nivo-prevNav {
background: none;
filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src="<?php echo WP_PLUGIN_URL . "/wp-nivo-slider/"; ?>images/arrow-prev.png", sizingMethod="crop");
}
</style>
<![endif]-->Save the file and test it. Now Nivo-Slider should work in IE6.
