Change image on expansion

I’m currently using images to as a trigger to expand/collapse content. I’d like the images to change when they are expanded and then switch back to the original when collapsed. I’ve looked around but can’t find information on anything similar.

Thanks for any support.

[expand title=”” trigclass=”noarrow buttoncenter” tag=”div”]
[visualizer id=”578″]
[/expand]

In the style.css sheet
/* Setting collapse-o-matic button placing */
.buttoncenter {
text-align: center;
display: inline;

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