Putting screenshots and diagrams into a PDF
A picture is usually a PNG for one of two reasons: something about it needs to stay see-through, or its edges are lines and letters that must not go soft. Both survive the trip into a PDF here. What decides whether the result looks right is the page size, and that choice is made for you unless you change it.
Which tool you need
Screenshots, diagrams or anything with lettering in it
PNG to PDF. Every pixel is kept as it was, so small type and thin lines look the same in the PDF as they did on screen.
A logo or cut-out that must sit on the page, not in a white box
Still PNG to PDF. Transparent areas stay transparent inside the file, which is exactly what is lost if the picture goes through a JPG first.
Photographs from a camera or a phone
JPG to PDF. Photographs are usually JPGs already, and a photograph gains nothing from being stored pixel-exact except size.
The pictures are pages of a document that already exists
Ask for the document. A PDF built from pictures of pages cannot be searched or selected, and no tool can put text back that was never in the file.
The result needs to go with other PDFs
Merge PDF, after converting. The picture PDF is a document like any other once it exists.
What is kept exactly
Nothing is resized on the way in and nothing becomes a JPEG, so an 8-bit picture reaches the PDF with every pixel where it started. A 16-bit picture is written at 8 bits per channel, and the result says so — that is the only case where anything is given up, and it is invisible outside photo-editing software.
Transparency comes across into the PDF itself rather than being flattened onto white, so a logo sits on the page. If you want a white background, put one behind the picture before converting; the conversion will not decide that for you.
Page size, and why the default is usually right
Each page is the same shape as its picture unless you say otherwise. For a screenshot that is almost always what you want: the page is the screenshot, with nothing around it and nothing cut off.
A4 and US Letter are there for a result that will be printed or filed with other paperwork. When you choose one, choose fit rather than fill for anything with lettering in it — filling the page crops whatever does not fit the paper's shape, and on a wide screenshot that is the edges of the window.
What to know before you start
- PNG files only. Photographs in JPG form have their own tool, and other formats need converting first.
- Text in a picture stays a picture. Nothing here reads words out of an image.
- Nothing is uploaded, and the finished PDF is saved to the device you are using.