dvdauthor changing menu images

[AlMan42]

I'm looking to use dvdauthor to automatically create DVDs with a basic template but some of the video files will be different. I can do this but we want to have a chapter selection menu with thumbnail images from part of the video clips to be displayed with the specific chapter select button. Is there a way to do this programatically at runtime????

[borax]

Do you already have the thumbnail images or do you need to extract them from the videos (like 1 image per 5 minutes)?
If the number and size of the images is the same for all chapter selection buttons, it can be done with some batch processing.

[AlMan42]

I will have the thumbnail images extracted from the different videos when they are recorded. They will all be the same dimensions. I'll just need to put them into the right spots just before authoring. What tool can be used for this?

[borax]

imagemagick