More than 400 images were posted online. Most showed just the test booklet, but 36 had the actual questions that appear on the standardized test.
Two of the 12 schools identified statewide are in San Jose -- Castillero Middle School and San Jose High.
The state Department of Education caught the breach back in April, but notified the San Jose Unified School District on Wednesday.
"What they did tell us was that two students, they had collected evidence that two students, one from San Jose High and one for Castillero Middle School has posted images of some testing material onto a social media website," district spokesperson Jason Willis said.
State officials worked with social networking websites like Facebook, Tumblr, Instagram and Twitter to remove them immediately.
California's Department of Education has analyzed thousands of test results trying to find discrepancies. Thursday a spokesperson said, "There is no evidence that what was posted had any effect on test results."
"Often it's really a sign of, 'this is my last test of my career,' or something they just wanted to do for just being a student,"
The Department of Education has yet to decide what action to take against the schools affected.
Valerie Ashtaputre's children, now in high school, attended Castillero Middle School.
"Kids do things without thinking; they'll take pictures and within two seconds it's out there on the Internet and it will never go away," she said.
Meanwhile, San Jose Unified has yet to decide what new measures, if any, to put in place to ensure this doesn't happen again.