Default Notification Shade dropdown image size?!

I want to add an image instead of the boring plain black background of the notification shade dropdown. What size should the image be to properly fit? TIA!
Sprint Galaxy S3 Retired
Sprint Galaxy S4 Retired


Sprint Galaxy S5
ROM: MOAR v2
Kernel: Stock NE5 Kernel with some tweaks
Theme: Velur (Nova icon pack)
Modem: NE5
Apps I NEED: TiBu, Google Now, Beautiful Widgets, Greenify (Donate), Xposed, 8sms, NiLS/NiLS FP


Awesome Collection of Android Apps from XDA Developers!
Collection of Apps for Android Wear (Alphabetized and Categorized)!