Which skin are you using? They're all different.

In Chameleon, choose Settings / Chameleon / Images / Image save protection and Download icon (check the first, uncheck the second). The image save protection (which disables right-click) is effective only in IE - FF ignores it.

In FotoPlayer, go to Settings / FotoPlayer / Options / Control Panel, and uncheck download (eliminates the download icon). Since FotoPlayer is a Flash skin, right-click copying isn't possible, anyway.

In Matrix, choose Settings / Matrix / Enlarged Images, and check Image save protection. Because this is a skin that uses Javascript to display the slide image, the protection against right-click saving is effective in all browsers.

In Boxer, choose Settings / Boxer / Navigation, and check Disable right-click on expanded images. Also effective in all browsers (Javascript again).

Some other skins may also offer this kind of protection.

There's an inescapable bottom line, here, however. If a person can see your image, he can save a copy of your image. That can't be prevented. In order to display your image, a copy of that image exists as a temporary internet file on your PC, and a knowledgeable user will certainly know how to save that copy. Using a Flash-based skin offers some additional protection, but even then, you can't prevent a user from doing a screen capture. Finally, a user who understands the directory structure of a Jalbum will know how to point his browser directly to the slide image on your web site. If the index page of your album is at www.example.com/gallery/index.html, your image files will be in www.example.com/gallery/slides, and in order for the album to work at all, that directory must be accessible.

You can watermark your images, and/or use the minimum resolution that looks OK on a computer monitor, but that's low-res enough to discourage image theft. But if you're going to display your images on a public website, there's no real way to prevent others from grabbing them.

A few years back I did some research on copyright case law (mainly USA), and in recent times have mounted a court case in Aust because my EBook was pirated.

Seems the law is fairly much the same worldwide, cept the "sweat of the brow" principle is still held in Oz.

But the USA leading case (re phone books) emphasises that the legislation is NOT simply to allow the owner of the work to stop people using the work but rather to enhance the arts and science, or some such words.

as such it would seem that a court would be very slow to entertain your copyright "rights" if the downloader made even the slightest "improvement" to the photo, though there are very few actual cases directly related to web images.

and not to forget that google may already have downloaded your images if they are any "good" so people don't even need to download first hand

here is the quote:

In 1994, Justice Sandra Day O'Connor, writing for the Supreme Court in Feist v.
Rural Telephone, reaffirmed the Constitutional basis for the 1976 Copyright Law:

"The primary objective of copyright is not to reward the labor of authors, but
to promote the Progress of Science and useful Arts. To this end, copyright
assures authors the right to their original expression, but encourages others
to build freely upon the ideas and information conveyed by a work. This
result is neither unfair nor unfortunate. It is the means by which copyright
advances the progress of science and art....(Copyright law) ultimately serves
the purpose of enriching the general public through access to creative
works." (1)

1. Feist Publications, Inc. v. Rural Telephone Service Co., 499 US 340,349
(1991)

Now I find that the very first thing I need to do to a "borrowed" image before "beautifying" it further is to use the straighten tool as some 95% of photos (incl my own) are not straight, not to mention a bit of cropping, resizing etc

I am wondering what a court might say merely to the straightening as to me it is a vital "enrichment" to make the photo bearable to view

and they said frogs were dumb!

This is easily resolved by placing an inex.html file in the slides folder with a redirect to somewhere else. Direct url access to the files in that folder is unhampered but if a user tries to navigate to the folder they will be directed somewhere else. Web servers can also be configure to not display contents of a folder if it does not contain an index file. Either way works.
Bottom line however, as EO points out, if you can view the file you can copy it.