Oh, the browser cache - wait:

[meta name="cache-control" content="no-cache"]
[meta name="cache-control" content="no-store"]

File - save as ... hm, works as long as you do not open your webpages in a new window that do not have a menue- and status bar but only the navigation bar.

Put a big watermark on your image that cannot be removed without destroying parts of the image - tubers don't want to put too much work into their new creation - cloning away the watermark is possibly to much effort for them.

You can slice your images, put the slices into the table as background and on top put a transparent gif, for those rightclickers that find a way to work around the script.

Every organisation rests upon a mountain of secrets ~ Julian Assange