To Covert all images from one folder from one format to another format Create file test.sh Add following line to that file for i in *png do echo $i temp=$(echo $i | sed -e 's|\.png||') convert -resize 640x200 $i $temp.gif done Save file Chmod +x test.sh Run File : ./test.sh Here I have used .png and .gif. We can try with other .jpg, .jpeg, tif, ttf, bmp etc.