get_the_ID() get get_attachment_image() fail inside function

My code works perfectly fine until I enclose it in a function. Variables can pass into the function just fine and when I echo them I can see they work. But none of these functions work anymore:

get_the_ID();
wp_get_attachment_image($image->ID, ‘thumbnail’);
wp_get_attachment_image_src($image->ID, array(150, 150));

Am I not allowed to put the loop inside of my own function? Once I remove the function it works as before. It seems to not be able to scope the vars properly.