i run a coderdojo and we have developed a system of cards that helps the kids creating a pong game with pygame zero.
in two hours of our weekly meeting, they manage to
- install the mu editor,
- create the game window
- download an image from the internet,
- put it in their game
- move the image around with the arrow keys
mostly by themselves.
loading the image is indeed one of the big issues they often face. but i'm convinced that it will often be an issue anyway: kids need some mentoring there.
(really, you cannot rely on the fact that they will be typing the file name correctly or that they will put the image in a specific directory, with the right extension).
this having been said, writing a full pong is much harder as in scratch. they do need some real mentoring for the further steps.
concerning your suggestion with yeso: for our setup, providing an image through the command line is probably not an improvement.
most of our kids are using windows or mac and we avoid forcing them to use the terminal during their first steps of "creating a game with real programming".
managing files is hard...