Technical question, particularly for Mac users

Dull and technical post.

A user of my website is geting the “Sorry, you don’t have a license to use this image on your website” message when they try to look at some of the cartoons.

This message normally occurs when a third party website tries to ‘hotlink’ a cartoon, ie use an image hosted on my site on their website. I have enabled something called ‘hotlink protection’, which makes this message appear. However, this message is being seen on my site, which is really not what should be happening. I was wondering whether anyone else is getting this problem, particularly those using Mac OS X version 10.4.6 and the Safari browser. This is a sample of a cartoon where the problem is occurring.

Any feedback would be welcomed, especially from Mac users.