Why are all my images, on http://www.theswordshop.co.uk coming out much darker in the front end than they are in the back end?

I'm on Magento 1.7.0.2

I'm also having an issue on a sister website http://theknightshoptrade.com/index.php/ They're both on different installs, with different themes and I don't believe they actually share any extensions

My images are all JPEG, 72dpi, dimensions of 650px x 650px, RGB and 8bits.

Here's an example of what my images look in the backend compared to the front end:

Image in correct colours (as seen in the backend)

Image desaturated (as is in the frontend