true remembrance final CG and easter eggs (minor spoilers)

There are some hidden effects that I've discovered in True Remembrance, such as:

-after the first playthrough, scribbled notes (somewhat amusing, probably from Black Iris and/or La) appear during the ending sequence on the moving film and during the scrolling where La's in a white dress

I do have a question though. apparently on the last row, bottom right there is a CG of La smiling with a scarf over her head and a brown color scheme, sort of like the banner picture of the English True Remembrance site for the story section. I got the picture to show up the first time, but I haven't been able to get it to show up again in any other playthroughs... which is odd because there technically aren't any choices in this visual novel. So I was wondering if anyone knew what exactly triggers that particular CG..