What is the url to header image

Hi there,

My forwarded emails do not display the header image.

I checked in Firefox this URL is correct (i.e. displays the icon):

http://www.mega-quick-sale.co.uk/sites/all/themes/mypushbutton/icon-bloc...

but if I put this in the forward module header image field, I don't see anything in the forwarded emails.

I tried cutting down the URL:

http://www.mega-quick-sale.co.uk/themes/mypushbutton/icon-block.png
http://themes/mypushbutton/icon-block.png

No luck. I am using multi-site by the way.

Any idea what is the correct URL?

Kind regards,
Marc.