Creating PDFs

Once again, you can use a tool from the ImageMagick suite as so. Notice the -density 150 argument. This is needed to set the display size when the file is opened up. Otherwise, it will be dynamic depending on your input file resolution, and if they are not uniform (and sometimes even if they are) it will choose different display sizes. Very annoying when you are perusing the completed PDF and encountering pages with different sizes. (this may have something to do with the operands it passes to ghostscipt that generates the actual pdg)

    convert -density 150 *.jpg MutiPage.pdf

Say you want to extract from a PDF? you'll get terrible text quality unless you specify a density up front, like below. (If you try to do a big PDF make sure to use a shell loop)

    convert -density 400% Tobins.pdf[75] -gray Tobins.png

or the more correct

    convert -density 288 Tobins.pdf -density 72 Tobins.png