UI Image Sequence From File (Platform Directory)

I’m trying to create an image sequence from user-taken screenshots for the main menu screen. However, I am unable to find a way to reference files outside of the project directory.

I understand the process of creating an image sequence with Project Directory files explained here:…rce/index.html

But it is the act of referencing external files which would be at a default directory of a given platform (ie- Steam’s screenshot folders or Epic’s screenshot folders.)

Is anyone able to point me to a resource that would help me in referencing these external files from their default locations for use in an Image Sequence?