#!/bin/bash
# part of ImageMagick

convert  -resize  600x450 -background gray10 -compose Copy -gravity center -extent 600x450 -quality 92 k-1210-Porto-IMG_5529-b.jpg k-1210-Porto-IMG_5529-b-600-ext-gray13.jpg


exit

#convert -scale 600x450 $1 `basename $1 .$ext`-ext.$ext;
#convert input.jpg -resize 800x600 -background black -compose Copy \  -gravity center -extent 800x600 -quality 92  output.jpg

ext=jpg

for i in *.$ext;
   do convert -scale 600x450 $i `basename $i .$ext`-600.$ext;
done