How can I know the person's name? I only have his picture. I'm from Philippines & I saw him in Corregidor Island also having a vacation.

If you don't know his name, it's unlikely that you're going to find it with just a picture.

Do you know any of his friends, a roommate, family?

The only way to find out his name is to ask either him, or someone that knows him.

Unless you work for the FBI and have face recognition software with a huge database in which that person just happens to be in, then you cannot find him.

Good Luck,
Javi