target="_blank" means that your link will open in a new browser window (so that the page upon which the link appears stays open).
I see target="_self" on affiliate banner code sometimes, it means (I believe) that the link will open in the same window (so that the page upon which the link appears is replaced by the target URL)
title and alt tags are entirely different, they simply reflect how the author chooses to describe their picture and have no bearing on "_blank" or "_self" targets.
I'd really recommend that you use
www.w3schools.com as a resource, that site provides really clear descriptions of different aspects of html code and you can try them out for yourself as well.