Pictures "pushed" at low quality

Finally I got my Denon AV1912 system to work both ways with Serviio. At first, I could "pull" images and music using the Sony Bravia smart TV and by using the menus displayed by the Denon amp. After going round the same loops many times, suddenly the Denon application on my laptop suddenly showed Serviio. At last I could "push" the music to the amp and speaker system. I have no idea what was stopping it or whether it will work when I next boot up the computer. However the user interface of the Denon is still clunky whether I push from the computer or pull from the menus on the TV, so a" play-to" facility from a list of files from within Serviio would be most welcome.

I am puzzled why images that are pulled using either the Bravia or Denon menus are OK, but when I "push" images from the Serviio server they are pixillated.

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each image has up to 3 versions, high, medium and low quality. it's possible when you push it picks up the lowest quality.