Video CD, a pre-DVD format that is very useful for making digital photo albums without recording expensive (and near-empty) DVDs. It's the best of both worlds: You can hand out something cheap that people can slot into their DVD player and view right away, and they can view the full-resolution photos in their PC or Mac.

The VCD 2.0 format lets you display 704x576 or 352x288 stills or video clips (the PAL MPEG-1 stream format is 352x288 at 25fps - a 1150Kbps bit rate), and you can add another top-level folder with whatever files you like (I usually create an "Originals" folder with the full-res photos).