QGIS is a great open-source GIS. With some effort, it should be possible to attach GPS coordinates to each JPEG and have it display them. However it's not going to be seamless at all.
What you're looking for is called "photogrammetry" : MICMAC is a rather well-known open-source software for that, but the interface is rather terse. I'm unfortunately not aware of open-source solutions that are as good and easy to use as Photoscan or Pix4D...