Convert pdf to image

http://askubuntu.com/questions/50170/how-to-convert-pdf-to-image

In the 

poppler-utils

 packages
there is the utility 

pdftoppm

 capable
of converting pages from a pdf file to ppm, png or jpeg format:

pdftoppm -png file.pdf prefix

will produce 

prefix-01.png

 etc.
for each page. By default the resolution is 150dpi. Increase the resolution (for higher quality output) as follows:

pdftoppm -rx 300 -ry 300 -png file.pdf prefix

To print only one page, use

pdftoppm -f N -singlefile -png file.pdf prefix

where 

N

 is
the page number, beginning with 1.