Photo memories

What does the option "Short", "Medium" & "Long" mean in a photo memory on iPhone?

I explain myself.

I create a memory > I play the movie > The pictures start to appear with music > If I tap the tree dots at the top right corner of the memory I get the menu > At the bottom of the menu I see the options "Short", "Medium" & "Long"

I thought it was the duration of the slides. But I have tried thre three options and the duratin of the slides are the same.

Does anybody what are these three options for?

Attached you will see the picture of the menu.

Thank you.