how do I reduce artwork on Smartphone screen

Hi all.

My setup - Pi 3b+ with IQAudio Digiamp+ Music library on USB hardrive Volumio V.2.526
My album art comes from a folder.jpg image in each album folder. image set at 300x300
LAN connection to view on my PC - volumio.local/playback
Hotspot connection to view on smartphone - Oneplus 3T

Everything works as it should work - perfect. The annoying issue is that on the phone the image is too large for the screen when in playback view and the edges of the image are lost.
I did have a couple of albums with jpg. images set at 150x150 but these still showed an image larger than the screen.
Any idea how I can correct this problem?