Photocasting: Serve the Right Picture Size
by Derrick Story
iPhoto 6.0.1 (correction: 6.0.2) has refined its ability to publish images in your library via RSS. And it works great -- in some ways almost too well. You need to be aware of the resolution you're sending out to control bandwidth requirements and how your images can be used.
When you enable an album for photocasting (highlight the album >Share > Photocast), you have the option of setting the image resolution you're sending out: small, medium, large, and original size. I tested these settings with a pictures I captured with a Canon Digital Rebel XT DSLR (8.2 MP) and a Casio EX P505 digicam (5MP). The original resolution for the Canon was 3456x2304 and 2560x1920 for the Casio. When I chose the "small" option, the image iPhoto served was 639x426 (Casio 640x480). "Medium" sent out 1279x853 (Casio 1280x960), "large" syndicated 1920x1280 (Casio 1920x1440), and "original" was as expected, 3456x2304 and 2560x1920 respectively. The output differences between the Digital Rebel and the Casio are because the Rebel captures images that are more rectangular than typical compact cameras.
If the goal of your syndication is for online viewing only, I recommend that you keep the image resolution at "small." Your recipients will need less bandwidth, and you don't have to worry about folks making high quality prints from your work. If you do want to enable printing, however, the "medium" output setting enables folks to make a photo-quality 5x7 print, and "large" can produce a very nice 8x10 print. The "original" output is of course dependent on the resolution of your camera.
I think for friends and family sharing, the "medium" setting is all most folks would need. This is a nice compromise between reasonable bandwidth requirements (200-500kb per image) and decent printing resolution. If you want to speed things up however, the "small" output is a svelte 70-150kb per shot.
If you'd like a broader overview of Photocasting, including a link to my sample Photocast, check out my recent post on The Digital Story: