Ideal image size for a slideshow?

Karen:

The key factor for iDVD slideshows is the image pixel dimension and ratio. iDVD uses photos at 720 x 540 pixels - Preparing images for iDVD slideshows. That is a 4:3 ratio so any size 640 x 480 or larger in that ratio can be used. iDVD will downsize the photos as necessary.

If the photos are not in the 4:3 ratio crop them to that in iPhoto before sending to iDVD.

NOTE: If you plan on using the Ken Burns effect in the iPhoto slideshow you'll want as large a pixel dimension as possible in the 4:3 ratio so the zoomed in image is not pixelated.

OT

Message was edited by: Old Toad

Any photo less than 640 x 480 will have black bands at the top and bottom or the left and right sides depending on the dimensions. Those whose width is closers to 640 than the height is to 480 will be scaled to fit the width with bands at the top and bottom. If the height is the closer dimension it will be scaled to the height with bands at the sides. It's like what you get when you add a portrait oriented photo. The height is used with bands on either side.

To see what it will look like create a test iDVD project, add a slideshow and add photos of different sizes, use the View->Show TV Safe Area menu and then play. You'll see which photos get bands.