Switched to pictures only (cover box and screenshot). Turned OMX back on. Thanks for the explanation.
Cheers

Thanks for the reply. So it does not matter much if I make them 320x240 or 640x480 or what else, as long as they are 4:2:0 YUV. I will definitely use the script, thanks!

@jerryfudd It's a raspi-config configuration error. Modify the
/etc/systemd/system/getty@tty1.service.d/autologin.conf
file and replace its contents with

[Service] ExecStart= ExecStart=-/sbin/agetty --autologin pi --noclear %I $TERM

then restart your system.