What folder on my phone is Plex uploading mobile photos from?

How can I find out (or change) the folder the Plex app is uploading photos from on my Android phone?

I’ve enabled mobile uploads in the Plex app, and two photos have uploaded successfully. However, I’ve no idea what local folder these photos are in, and Plex is not uploading any photos from the default folder my phone’s camera saves to. The two photos Plex chose to upload were taken last year, and I cannot find them either on internal storage or the SD card when I searched (using both ES File explorer on the phone, and using Windows on a PC with the phone attached as an MTP device).

Hope you can help as this looks like a great feature, if I can get it to work.