Displaing photos is very slow, is there a way to speed it up?

Hi, I recently moved my photos to the Plex server running in a Synology DS1515+ NAS. Every thing is great, except that when I go to my TV, using an AppleTV 3 connecting to my plex Server using Plex Connect, I do all, but the photos display takes more than 10 seconds in most cases. Doing the same, but directly from my iPhone 6, using the plex software on the iphone, get similar delays, so My guess is that the delay in the display is not the plex client (ios plex or AppleTV3+Plexconnect). Then I did another test, I just mounted the Plex Photo Library using the AppleFileSharing (Mounting the remote drive as afs://) and then just selecting the photos and using the Apple QuickLook native software, the display of the photos is instantaneous. So, the network is ok, and the NAS speed is ok. Maybe the Plex Server is trying to transform the photos to another format that takes to long. Any help will be welcome, I want to use plex as my primary Photo Library, and the speed of the display of the photos is a KEY for this. I not expect miliseconds, but 1 second I think will be reasonable.

Any experience with the Photos, please share it.

In what regards PlexConnect, can you pls try the latest version and set phototranscoder to auto ? When I say the latest PlexConnect I do not mean the latest Synology installer, I mean the latest version in github.