But when you are creating custom presentations, keeping your file size small becomes a real challenge. Use the proper picture type and be aware of the differences in file formats. On Windows-based computers, PowerPoint 97 and 2000 let you choose from among more than 17 different file formats when you're importing photos or illustrations. But as sophisticated and varied as these compression algorithms have become, no one has yet devised a foolproof way to figure out which format will work best in a given situation.
Experience is the best teacher.
After many years, I've now boiled my own choices down to three file formats for photos and one for illustrations. This is old hat to designers, but presenters might need some quick tips when looking for the right resources. JPEGs are your best bet for photos. For illustrations or clip art, stick with the WMF, which gives you smaller files than most other options for clip art, plus the flexibility of editing them directly in PowerPoint. If you're a designer who creates your own images, as I do, you'll probably still want to rely heavily on JPEGs for most of the photos you import into an overall graphic.