The Download Button on the Button Bar gives the user the ability to directly download individual images. SimpleViewer does not feature the ability to save all images in a gallery so it sounds like your clients may be trying to save all images using a browser-specific option rather than a control within the gallery.

Make sure that you are using the latest version of SimpleViewer-Pro (v2.3.1) to ensure that any bugs which were present in previous versions but have since been fixed are not contributing to your problem.
If necessary, please see the Upgrading SimpleViewer-Pro support page.

When you say that you 'send slideshows out to my clients', do you send your clients a link to the gallery which is uploaded on a web server or do you send them the SimpleViewer-Pro gallery itself on a disc?
The Download Button will work only when the gallery is uploaded to a web server.

Here is a screen shot of what the "activity" window is saying on their computer. http://joehendricks.com/images/ss.png
He is running snow leopard.
When I tried to download a picture from the slideshow on his computer, it says "what do you want to save it as?" and only gives an "all files" option. It didn't seem like the .jpg extension was attached for some reason

Does this mean anything to you?

The activity window may be showing the images in the gallery that are being preloaded by the browser. By default, SimpleViewer will preload the current page of thumbnails to allow quicker transactions between images (rather than loading each image only when it is selected which could result in a slight delay as the browser loads it). The images which are preloaded is controlled by the imagePreloading configuration option.

The download window shows only "Save as type: All files (*.*)" to save the images in the gallery exactly as they are (whether they are .jpg, .gif or .png files). (There is no option, for example, to save a .jpg file in the gallery as a .png file.)

However, having investigated further, there is a bug which prevents the Download Button for functioning when a baseURL is used which starts with a leading slash to denote the root directory (as used in Showkase).
I have logged a bug report with the developers and hopefully it should be fixed in the next version.

In the meantime, perhaps the easiest fix would be to open the generated gallery page (http://joehendricks.com/sv2/nicholasmeredith/index.html) in a plain text editor and change the baseURL in the gallery's embedding code from:

baseURL : '/sv2/nicholasmeredith/'

... to:

baseURL : 'http://joehendricks.com/sv2/nicholasmeredith/'

@sestrada

Please ensure that you are using the latest version of SimpeViewer-Pro (v2.3.1).
Please see the Upgrading SimpleViewer-Pro page for details if necessary.

Also, please post the URL to your gallery so that I can take a look.

The only thing I can think of at the moment is that the problem may be caused by the fact that your gallery is hosted on a https:// secure server.
Unfortunately, I do not have a https:// server on which to test.
Are you able to upload your gallery (changing the https:// references to http:// in your gallery's XML file) to a http:// server to see if the download button works there?
If it does, then it looks like the https:// is the root of the problem and I will log a bug report with the developers.
Thank you for your help in tracking down this bug.

Incidentally, the Download Button uses the imageURLs rather than the linkURLs.

Also, as your gallery does not use a baseURL starting with a leading slash (which is the scenario which the known bug affects), you should be able to use relative paths rather than absolute paths in your 'gallery.xml' file.