Brad Brace has been uploading a photo to the Internet every 12 hours since December 30, 1994. The 12hr-ISBN-JPEG project is a continuous posting of "sequenced hypermodern imagery," usually black and white photos of city life, which are simultaneously posted to FTP sites, mailing lists, and Usenet's alt.12hr newsgroup.
So, does that make the 12hr Project the first photolog?
July 31, 2003: I e-mailed Brad, and he said that a complete archive doesn't exist; even he doesn't have copies of all his photos. I've compiled a partial archive of all the photos I have, about 780 so far. If you have any more, or know where to get them, please let me know.