It's no secret that attending Comic-Con has become a challenge. Obtaining a badge and a place to sleep is a test of fortitude. It wasn't that way when I started attending in 2006, and it especially wasn't that way in 1982.
Yes, the photo that's been going around the internet is from 1982 not 1983. It was taken by Alan Light and commemmorates the 13th event. The convention started in 1970, but it happened twice in that year. The first event in 1970 was a minicon used to raise funding for the actual event that happened in August. Both were big enough to count in numbering. In 1982, San Diego Comic-Con took place from July 8th-11th - the only year the dates line up with what's shown on the marquee in the above photo. The comic convention happened at Hotel San Diego.
Other glimpses at the 1982 event from Alan Light:
The dealer's room:
A bigger crowd outside:
And yes, a Women in Comics panel! From left to right, the line-up features: Dori Seda, Unknown, Jan Duursema, Trina Robbins, Carol Kalish, Jo Duffy, Lee Marrs, Catherine Yronwode, Carol Lay, Terry Boyce, and Melinda Gebbie.
You can see more photos from Comic-Con 1982 on Flickr.