Bulk operations on images in Linux - How to bulk convert PDF files to PNG

One of our clients sent us images they want to put in the website as pdf files. There were 100 files each containing a single image. Opening each of these in gimp and then saving it as pngs was a nightmare. For all such situations, ImageMagick is there for your rescue. With mogrify - a command utility available in the ImageMagick package, bulk converting all these pdf files to png was child's play.

mogrify -density 400 -format png -resize 25% *.pdf 

This converted all the files to png within seconds.