For help with sizing images appropriately for your PowerPoint presentations, check out this short YouTube tutorial video produced by the Visual Resources Center in the School of Architecture at the University to Texas-Austin. Now you know ....
Some of these tools we've tried and recommend (as noted). All others are tools we've heard about but don't have direct experience with them. Many of these tools are free for students and educators.
Image Storage & Search Tools
Use these sites to find free--but not necessarily copyright free--images online.