Mounting my photos folders on my Raspberry PI to use as a bridge to a PC

I have been uploading my photos to my synology and I want to access them on my Raspberry PI. This is the first step to use the PI as a bridge. I am not sure what the best way to mount the drive. I have been scouring You Tube and there seems to be a couple of ways to do this.

I ultimately want to use the the pi to emulate a usb thumb drive so I can use a non-networked computer to access the photos on my nas.

I bought a new Raspberry PI 5 and it is up and running, I read that I can use a program called Gadget to achieve what I want to do but I need to get access to the photos on the pi.

I currently have to log onto another computer and down load the pics to a thumb drive to access them which is getting old.

Does any one have advice for me?