When did he join MCR?
He joined My Chemical Romance in 2002. When Frank decided to join MCR, he was still in Pencey Prep. He was friends with the guys from MCR since they worked in the same recording studio. He watched all of their practices. He also listened to there first demo all the time. Later on when Gerard Way decided that the band needed another guitarist, Frank took that position and left Pencey Prep. He was the last member to join the band. (not including drummer replacements that happened over the years)
What did he work on with MCR in the start?
When he joined, the band was working on their first album. This album is I Brought You My Bullets, You Brought Me Your Love. Because of his late start to the band, he was only featured on two of the songs. These are Early Sunsets Over Monroeville and Honey This Mirror Isn't Big Enough For The Two Of Us.
What did he look like?
Franks appearance changed a few times over the course of these first few years. Images of him and the rest of the band from this time are below. There is also an image from the first MCR show. It is the second picture down all the way on the right.