Configurable Products Images Not Showing

[christopher_oliver]

I have a configurable product set up with two simple products associated to it. For demonstration purposes I have used the configurable product "Pet Test" with the two simple products "Test Product Dog" & "Test Product Cat". The url for demonstration is: https://www.design-a-cake.co.uk/pet-test.html

The initial problem I had was I got the error: Invalid method Mage_Catalog_Block_Product_View_Media::isGalleryImageVisible

I added the function as such in Media.php that I found in a template file online (cannot be sure if it is correct)

    public function isGalleryImageVisible($image)
{
    if (($filterClass = $this->getGalleryFilterHelper()) && ($filterMethod = $this->getGalleryFilterMethod())) {
        return Mage::helper($filterClass)->$filterMethod($this->getProduct(), $image);
    }
    return true;
}

Now the url loads fine but it does not get the child images when they are selected in the dropdown, it simply shows the parent image but larger? The description changes but is duplicated. If you look at the url you will see quite clearly the issues.

Does anybody have any ideas about this? Thank you.