Picture, photo and image. what is the difference?

English is not my mother languaje, I'm actually studiying it, and this question was wondering in my head for so long, even here in steemit, has different tags of photos and pictures, when in fact, they all look like the same thing, so I asked to my english teacher, What is the difference? and that is what he said:

An image refers to something you see, doesn't neccesarily have to be something physical, for example: if you are on a lake and you see yourself on the water, that can be called an image, an image of you reflected on the water.

source image: Universal.org http://www.universal.org.ec/el-exterior-es-el-reflejo-del-interior-de-cada-uno/

But also, an image, include, 'photo' and 'picture'.

A picture originally referes to something made, like a painting, something who was made by a person.

A self portrait made by artist Vincent Van Gogh by himself.

A photo is a image but generated by a machine, not by a person, like cameras.

"the first selfie"

Source image: 'Univision.com http://www.univision.com/noticias/crees-que-la-selfie-es-un-invento-reciente-la-primera-fue-tomado-en-1839-fotos'

A photo I took of and little harbor.

but adavacing on time and technology, the original using of this words is gettin lost, so, it's normal you call a photo, picture, and vice versa, and there is no problem.

Actually the way he said it made very clear for me, and i find out interesting, it's not a live of die matter but it's enterntaiment to know that kind of stuffs.

Just want to share my story, I hope you find it useful.

Cheers!