Hosting photos on the server would involve much, much higher bandwidth, CPU, storage and therefore cost than this server (supported and maintained by voluntary contributions) can provide, that's why in common with just about every similar site, photo hosting has to be elsewhere on the web.
There will be someone along in a moment to talk about Dropbox, Google photos allows you retain copyright over your photos and share exactly what you want. In fact, I suspect that most other than Flickr, facebook, Pintrest and the like which try to make money out of your photos are similar.