convert thumbnail.gif \( +clone -alpha extract \
\( -size 15x15 xc:black -draw 'fill white circle 15,15 15,0' -write mpr:arc +delete \) \
\( mpr:arc \) -gravity northwest -composite \
\( mpr:arc -flip \) -gravity southwest -composite \
\( mpr:arc -flop \) -gravity northeast -composite \
\( mpr:arc -rotate 180 \) -gravity southeast -composite +write mask.png \) \
-alpha off -compose CopyOpacity -composite rounded_corners.png
From then on for the same size input, use the mask in place of all the code in the parentheses before the +write mask.png
Code: Select all
convert thumbnail.gif \
mask.png \
-alpha off -compose CopyOpacity -composite rounded_corners2.png