From what I can make out, it is not a crack. It's the joint. It's like how a cricket bat always has the V line coming from the handle. However, I wouldn't take advice from someone I don't know over the internet.
.... Don't worry tooo much .... I too got this when i painted my guitar ..... This is due to moisture .. when u keep your guitar in open environment .. then the wood gets ... swolen up ( i dont know the other word : ) Due to which crack appear at joints .... It also happens if the guitar is half decade old .. :annoyed: Or it can be due to physical damage