When you find you are getting into Custom User Interface (CUI) building Background images some times are used.
When using images it is best to get the image file to fit the screen resolutions so here are the resolutions for the Velocity Panels.
AT-VTP-550 landscape 768 x 432
AT-VTP-550 portrait 432 x 768
AT-VTP-700 landscape 1024 x 600
AT-VTP-700 portrait 600 x 1024
AT-VTP-800 landscape 962 x 601
AT-VTP-800 portrait 601 x 962
AT-VTP-1000 landscape 2180 x 800
AT-VTP-1000 portrait 800 x 1280
AT-VTP-1000G landscape 2180 x 800
AT-VTP-1000G portrait 800 x 1280
AT-VSP-800 landscape 1090 x 681
AT-VSP-800 portrait 681 x 1090