About PDF and Image conversion

Pdfinfo is mostly installed on Linux. For Windows you can get it from foolabs.com. Pdfinfo simply prints the Information stored in the PDF Info Dictionary like this:

Producer:       Acrobat Distiller 4.0.5  for Macintosh
CreationDate:   12/01/03 13:19:23
ModDate:        12/03/03 12:59:56
Tagged:         no
Pages:          50
Encrypted:      no
Page size:      964 x 694 pts
File size:      411408 bytes
Optimized:      yes
PDF version:    1.3

You can use it to convert PDF documents page by page with the Ghostscript argument -dFirstPage and -dLastPage. Because Ghostscript doesn`t have a command line argument for getting the pagecount of a file, you can use pdfinfo for that. Simply programmatically use the last Number from line 16 from the output of pdfinfo..