How can I convert a pdf page to jpg with its original resolution?

[Jean-Pierre Coulon]

At present I measure the size of a pixel magnifying the page a lot with acrobat reader. I measure the page width. width/pixel gives me the number of pixels for the width. I try to convert with variable densities till identify gives me the same size. Is there a more productive and more accurate procedure?

[snibgo]

I think you mean that you have a PDF page with an embedded raster image. You want to know what density to rasterize the page such that the raster image is not resampled. Is that the question?

The answer is to use pdfimages, not ImageMagick.

[Jean-Pierre Coulon]

This PDF page was made with a scan but I don't know how it was converted to pdf. You understood my question. Could you please provide the link to pdfimages? Is it free?

[fmw42]

see
https://en.wikipedia.org/wiki/Pdfimages
https://poppler.freedesktop.org