There are probably several ways, but I would do it like this.
1) Use firefox as your browser
2) Go to Tools -> Options -> Content -> Enable Javascript -> Advanced
3) Uncheck the 'Disable Or Replace Context Menus' Options
At this point, you should now be able to right-click on the picture and save an image. You will notice though that the image you save is the scrolling watermark. When the web page is rendered in your browser, it overlays this watermark image over the actual running picture, hence you can't save the running picture. To get round this, you need to stop the browser rendering this watermark image.
My solution would be..
4) Download and install the AdBlock Plus addin from http://adblockplus.org/en/
5) Go to the photo you want to download -enlarge it first
7) Right click the picture, select Adblock Plus: Block Image
8) Select 'Add Filter'
9) Right click on picture, select 'View Background Image'
10) Right click on picture, select save as....
You now have the pic on your hard drive - still has the fixed watermark on it, you need to play with photoshop to get rid of that.
Bear in mind this is possibly illegal if the photo is copyrighted, so this is for technical interest only. I obviously can't condone anyone actually doing it!
Edited: 10/05/2012 at 14:01