Pano2VR does not stitch the images. You must first bring your images into stitching software like, PTGui or Hugin to create the correct projection (i.e. equirectangular) before importing them into Pano2VR.
Some cameras automatically output a 2:1 equirectangular image (like the Ricoh Theta). You can import these images directly into Pano2VR.
Bring your single image or group of images into Pano2VR by doing any of the following:
Drag a folder containing images on to the Viewer or Tour Browser in Pano2VR Pro.
Click the input button in the Toolbar and navigate to your image/s.