Use ImageMagick to convert pdf to png
ImageMagick is a powerful command line image processing package with a number of features you could install it using the following command :
sudo apt-get install imagemagick or sudo yum install imagemagick
After installation is over to convert say sample.pdf to sample.png issue the following command
convert sample.pdf sample.png
or
convert sample.pdf sample.jpg
Now if sample.pdf has multiple pages ImageMagick would convert each individual page into a separate file for example : 1st page as sample-0.png , 2nd page as sample-1.png and so on .
