Photo stitch problem

[Ride2017]

This is driving me absolutely crazy. I've got 2 separate photos (before & after shots) that I need to stitch together to create 1 photo. Been all over Google etc but there doesn't appear to be anything that would allow me to do this via either an iPad or Mac.

Any advice would be greatly appreciated!

 

[PeteXXX]

Gimp? I don't use it personally, but it might do the job.
Edit: it might be just for Windows though.

 

[Specialeyes]

I use a little download called Autostitch at to create panoramas and wide-angle survey shots. There are probably Photoshop plug-ins that do the same, but it works for me. Available here: http://matthewalunbrown.com/autostitch/autostitch.html