Andy,
I've never used Premiere for this. When you said picture gallery, I assumed you meant a slide show type thing. Since you have hundreds of images, it just seemed a lot of work to set it up in Premiere. While you can set a single transition for each one in Premiere, in ProSho, you can set random transitions and it also has a variety of more elaberate transitions. You then generate the DVD directly in ProSho. You can set the sound track to directly reflect the length of the slideshow ie set a slide / second automatically.
(Sorry to ramble and I don't have any connection to Proshow, I just like it for slide shows).
If you wanted to use an Adobe Product, I'd consider After Effects per this tutorial
http://www.videocopilot.net/tutorials/elegant_slideshows/
John Rich
JOHNR
