Hi all
I have updated the plugin with two minor fixes. You can read the detailed information at my homepage: http://tenzer.dk/zenphoto-sitemap-101
jollywood, a sitemap was generated when you tried it out on my gallery, but your browser was simply interpreting the page as normal HTML, which means that it only showed the links. If you chose "View source" you would see the correct XML file.
One of the changes in the new version is that the correct XML content type header is sent out, which informs your browser that it is receiving an XML file.
The plugin doesn't specify any priorities any longer, since it didn't work out correctly before. In order for priorities to work correctly, all the URLs has to be in the same XML file, since the priorities are only compared with other URLs in the same XML file.
Since that would be a larger piece of work that would need to be put into that, I just skipped out the priority part for now. It may be the next thing to do for the plugin.
It's hard for me to specify the change frequency, as that purely depends on the activity in the gallery. Some logic to calculate how often new pictures are added, and how often new comments are posted would probably have to made then, which makes the plugin much larger than what I aimed it to be. I just wanted to have it as a file that is put into the Zenphoto plugin folder, and just works from there.
The other approach to this would be that the administrator of the gallery simply specified the change frequency for each type of page (root, gallery, picture), and then some kind of interface would have to be made for this in the administration interface, but that is probably easier than coding the above described logic into the plugin.