I NEED HELP FIGURING OUT HOW TO PRINT FROM COMPUTER?

I AM NEW TO COMPUTER AND NEED TO FIGURE OUT HOW TO PRINT FOUR PICTURES FROM COMPUTER OF hERNAN cORTEZ FOR MY 6TH GRADE SCHOOL PROJECT. mY TEACHER SAID THE PICTURES HAVE TO BE 4BY6 INCHES IN SIZE AND I MUST HAVE FOUR OF THEM TO PUT ON A POSTER. PLEASE HELP.