Copyright free images mean that no referencing is strictly needed, but it is still courtesy to cite where images came from. This is an image that is relevant to the learning in my classroom at the moment - I am in 6/7 and we are learning about the democratic process in a integrated unit. This image of people standing for hours in queues in Africa to vote could be used in SOSE - learners could pick one person out of the crowd and write a brief "biography" - trying to expose children to different viewpoints.