May Day is Lei Day in Hawaii

Celebrations in Kapiolani Park for May Day today.   This one won the Mayor's Grand Prize.  Done by Melvin Tracy Labra using 'a'ali'i, ti leaf (ki), maile, 'ohi'a (lehua), pala'a, palapalai, pukiawe.  The display is glossy, folded-back ti leaves and resting on monstera leaves.   There are a few others which I liked better this year, and some beautiful hat lei. 
 
This is the Mayor's Grand Prize 2018.

Question:  Does anyone know of a simple, free program to collage fotos?