Get Screenshot
(HTC AMAZE is 544x960)
adb pull /dev/graphics/fb0
ffmpeg -vframes 1 -f rawvideo -pix_fmt rgb32 -s 544x960 -i fb0 screenshot.png

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It’s important to have the correct resolution
#get screen size 
dumpsys window | grep mUnrestrictedScreen

#and link fb0
ln -s /dev/graphics/fb0 /dev/fb0

This is my PengPod
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sudo adb pull /dev/graphics/fb0
ffmpeg -vframes 1 -f rawvideo -pix_fmt rgb32 -s 800x480 -i fb0 screenshot.png
avconv -f rawvideo -pix_fmt rgb32 -s 800x480 -i screen screenshot.png

display screenshot.png

Display Random Static to Screen
cat /dev/urandom > /dev/graphics/fb0

Save Screenshot while on Device
cat /dev/graphics/fb0 > screenshot

Save Screenshot while on Device
cat screenshot  > /dev/graphics/fb0