What Is the Best Way to Fit Many Pictures Together in a Grid without?

What is the best way to fit many (about a hundred) pictures together in a grid without hurting each picture's quality?

That depends on where the photograph was taken
 but, basically, nothing. First off, a picture with you in it is not “your” picture. By international law, a photograph is the legal intellectual property of the photographer. You do not own the photons that bounce off of your body. You have no expectation of privacy in a public place, therefore you cannot claim your privacy was invaded. A photograph of you taken in a public place can be used without your permission for almost any legal purpose except commerce (which, in legalese, basically means “advertising”). An illustrative court ruling is Nussenzweig v. DiCorcia. If the photo was taken in a place where you did have a reasonable expectation of privacy, you can potentially sue for invasion of privacy. In order to prevail in a privacy suit you have to prove, through preponderance of evidence, that you sustained damages, and the court can only award you the actual documented damages you sustained. You will wind up spending several thousand dollars in legal fees and it will take months if not years to resolve through the courts. Barring documentation of actual damages the most you’ll gain is an injunction telling them not to use the photo. Trying to suppress publication of an embarrassing photo can be counter-productive because the photo becomes part of the public record. See the Streisand effect.