AJT

To just display picons on the LCD screen, go to Menu>Setup>System>Display>LCD4linux

Press Blue - Set On. Scroll down to select Picon path, and continue scrolling down turning off anything else you don't want ie Clock, Program Name etc. Once you have got rid of the stuff you don't want, you can resize the picon to fill the whole display. Don't forget to press Green to save.

For the VFD problem, I would try updating the VFD controller. Menu>Plugins>Firmware Upgrade and press right arrow to select VFD Controller.