Content management - Dynamic Image Gallery

I have made a site for an artist with a dynamic gallery using an xml file. I am trying to create a way for him to update the gallery by simply uploading his new photos through a html form.

I have an image upload form which puts the images in the directory which the xml file references but i cant figure out how to generate a new xml file to show all the new pictures.

Does anyone know a place with a tutorial that explains this?

Are there any easier ways to achieve an updatable gallery?