Why not using the 770's normal Images procedure. It's very good and flexible enough, quality is really splendid, zooming shows nicely picture details, re.: Help/770. E.g. pictures in a directory can be viewed back and forth with arrows.
I use 770-Images a lot for a "family photo show machine" in family gatherings.
Transferring pictures PC<->770 is a standard USB procedure, re.: the 770-manual.