Resize
Resizing an image
convert dragon.gif -resize 64x64 resize_dragon.gif
Ignore Aspect Ratio ('!' flag)
convert dragon.gif -resize 64x64\! exact_dragon.gif
Only Shrink Larger Images ('>' flag)
Never enlarges images
convert dragon.gif -resize 64x64\> shrink_dragon.gif
Percentage Resize ('%' flag)
convert dragon.gif -resize 50% half_dragon.gif