Ciro Santilli Crop
20 pixels from the bottom of the image:
convert image.png -gravity East -chop 20x0 result.pngconvert -size 512x512 xc:blue blue.pngconvert -size 256x256 gradient: out.png
convert -size 256x256 gradient:white-black out.png
convert -size 256x256 gradient:red-blue out.png
convert -size 256x256 radial-gradient: out.png
convert -size 256x256 radial-gradient:white-black out.pngDigits 0 to 9, white on black background:
for i in `seq 0 9`; do convert -size 512x512 xc:black -pointsize 500 -gravity center -fill white -draw "text 0,0 \"$i\"" $i.png; done