Usually, WordPress stores the images in the Upload Library. If you wish to get more from the uploaded images, for example, store them into explicit folders, you can try out several plugins for image libraries, for instance, EnviraGallery or ModullaImage Gallery. If you would look, there are lots of them created for WordPress.
I don't see why anyone would host a WordPress based site on AWS. It is not that Amazon isn't good, they are. However, they are much more expensive compared to any middle-sized web hosting provider. On top of that the support that one would get from a web hosting company would be much better than the Amazon's one.