ImageMagick resize with round edges

magick.rb

in_pic = "in.jpg"
out_pic = "out.jpg"
radius = 25 
size = "500x500"
bgcolor = "white" #JPG doesn't support alpha channel, write "None" if you want transparent edges for PNG files
cmd = "convert #{in_pic} " +
      "-resize #{size}! " + #comment out this line if you don't want to resize
      "\\( +clone -alpha extract " +
      "\\( -size #{radius}x#{radius} xc:black -draw 'fill white circle #{radius},#{radius} #{radius},0' " +
      "-write mpr:arc +delete \\) " +
      "\\( mpr:arc \\) -gravity northwest -composite " +
      "\\( mpr:arc -flip \\) -gravity southwest -composite " +
      "\\( mpr:arc -flop \\) -gravity northeast -composite " +
      "\\( mpr:arc -rotate 180 \\) -gravity southeast -composite \\) " +
      "-alpha off -compose CopyOpacity -composite -compose over " +
      "\\( +clone -background black \\) +swap -background #{bgcolor} -layers merge #{out_pic}"

`#{cmd}`