Optimal Bitmap format for PNG

[qooApps]

Every PNG in an app will be transcoded to TXI, I would think for faster access. I found out, that color gradients will not properly displayed, so I tested some other PNG formats than PNG-24 (full RGB).
I've got the best results using a PNG with indexed colors (PNG-8) and a palette of max. 32 entries and dithering.
@JonFitbit: Do you use color reduction for your TXI format? What's your perefered image format for the origin PNG?

[JonFitbit]

Are you able to provide some same images which have issues? I've not personally had any issues with 24bit png's.

[qooApps]

I have posted my results in the discoord chat, but here you can see the difference: left is original 24-PNG and on the right there is the screenshot from the test app, which included it as a fullscreen background image:

On the right side you can see lines in the gradient, which indicates some color reduction.

The original 24-bit PNG