If you can see it, you can steal it. Flash doesn't protect you from screengrabs. To protect from Save As, you can use a table and overlay the image with a clear GIF file. Make a 1 by 1 pixel GIF, use image height and width tags to stretch it to same dimensions as the image to cover. Make your photo the table cell background, and put the 1x1 GIF image in there as the foreground. When they save the image, they'll just be saving the clear GIF with no real image.
This only stops people from dragging-and-dropping images or Save As, but won't stop anybody from screenshotting it or going through the HTML and linking to the original. Flash will do the same thing. But there's always the analog hole... if someone can see it, they can steal it.