extracting images from PDFs
pdfimages , packaged in poppler-utils in Debian, can extract images from PDFs. Its default output format is weird. It would be nice to have it just extract the images, in whatever format they're in, by default. But to get this behaviour you need something like the option -all. But even that isn't specified as "what comes in, goes out". Instead, it is specified as: Write JPEG, JPEG2000, JBIG2, and CCITT images in their native format. CMYK files are written as TIFF files. All other images are written as PNG files. (I can't get blogger to remove that double spacing from the paste). The reader is left hoping that "all other images" permitted in the PDF whatever-version format (PDF spec is a bigly moving target) are PNG. But I wouldn't bet on it. So some obscuro format might be getting converted to PNG still. The other gotcha is this from the SYNOPSIS and command-line usage summa...