Choose some photos randomly

I'm new at coding. I want to make a program in visual studio. I've a photo, and on this photo I have small pictureboxes like pins on a photo. I have 30 picterboxes, and i wan't to get 10 visible of the 30 randomly, and the rest of them (20) be invible, like when you making a test/quiz randomly generated. Can somebody help me how to make this? Sorry for my english.