Magento resize() image quality: dirty white background

Question

I have a client who is seriously unhappy with the way their product thumbnails are rendering on Magento.

The dodgy appearance is noticeable on two accounts:

Answer 1

quick grep shows that you are able to set this on product_image object

app/code/core/Mage/Catalog/Helper/Image.php:105:     * Set image quality, values in percentage from 0 to 100
app/code/core/Mage/Catalog/Helper/Image.php:107:     * @param int $quality
app/code/core/Mage/Catalog/Helper/Image.php:110:    public function setQuality($quality)
app/code/core/Mage/Catalog/Helper/Image.php:112:        $this->_getModel()->setQuality($quality);
app/code/core/Mage/Catalog/Model/Product/Image.php:38:    protected $_quality = 90;
app/code/core/Mage/Catalog/Model/Product/Image.php:88:     * Set image quality, values in percentage from 0 to 100
app/code/core/Mage/Catalog/Model/Product/Image.php:90:     * @param int $quality
app/code/core/Mage/Catalog/Model/Product/Image.php:93:    public function setQuality($quality)
app/code/core/Mage/Catalog/Model/Product/Image.php:95:        $this->_quality = $quality;
app/code/core/Mage/Catalog/Model/Product/Image.php:100:     * Get image quality
app/code/core/Mage/Catalog/Model/Product/Image.php:106:        return $this->_quality;
app/code/core/Mage/Catalog/Model/Product/Image.php:331:                'quality' . $this->_quality
app/code/core/Mage/Catalog/Model/Product/Image.php:387:        $this->_processor->quality($this->_quality);