How to extract images from a PDF
A screenshot of a picture inside a PDF is a blurry copy of a copy. Here is how to get the original image file out instead, at its real resolution.
Why a screenshot is the wrong way to do this
Taking a screenshot of a photo or chart inside a PDF captures it at your screen's resolution and re-compresses it as a new image, which is always a downgrade from what is actually stored in the file. A PDF stores each embedded image as its own file internally, usually a JPEG or PNG, at whatever resolution it was placed at, often much higher than a screenshot could ever capture.
In Adobe Acrobat
Acrobat Pro can export images from a PDF via File → Export To → Image, which pulls out embedded pictures at their stored resolution, but the feature needs a paid Acrobat subscription; the free Acrobat Reader has no image export option.
Command-line tools
Tools like pdfimages, part of the free Poppler utilities, extract every embedded image from a PDF at full resolution from the command line, which works well for someone comfortable with a terminal but is more setup than most people want for a single document.
Extracting images without uploading the PDF
Stayput's extract images from PDF tool scans the document in the browser tab and saves every embedded picture as a separate PNG or JPG, at the resolution it was actually stored in the file, not a screenshot's resolution. It works on every image in the document at once, with nothing uploaded to a server to do it.
Questions
Why is a screenshot of a PDF image lower quality than the original?
A screenshot captures the image at your screen's resolution and re-compresses it, while the PDF itself stores the picture as its own file, usually at a higher resolution than any screenshot could reach.
Can I extract every image from a PDF at once?
Yes, Stayput's extract images from PDF tool finds and saves every embedded picture in the document in one pass.
What format do the extracted images come out as?
PNG or JPG, matching or closely approximating how the picture was originally stored in the PDF.
Does this work on a PDF made from a scan?
A scanned PDF is usually one full-page image per page rather than several embedded pictures, so extracting images from it saves each page as a picture rather than pulling out separate photos.