The ownership of images and how the law applies is old and has been around since printing was invented and arguments in the 19th century over literary materials. However we are now in a world dominated by electronic networks and storage, where most people have a mobile telephone capable of photographing any image and the wish to record what they have seen. Generally as the creator the artist owns the copyright unless it has been signed away under some supplier's terms and conditions. Who do you think owns your images once they are on Facebook and Instagram? Do you know what social media T&Cs say about your rights? If you have not read them you might like to do so!
In the UK the Intellectual Property Office, part of the Patent Office, gives guidance on these matters. Their advice is published and you can find it on the internet or of course you can consult a lawyer. If you are interested then have a read of the following IPO guide on digital images and copyrights - click here for a download.