PNG quality in PDF
With Original quality, PNG images are embedded losslessly, so screenshots and diagrams stay sharp. PNG files can be large, though. If the PDF is too big to share, choose Smaller file to convert pages to JPEG, which works well for photos but is softer for fine text.
Transparent areas in PNGs appear white in the Smaller file option.
Page size, orientation and margins
A4 (210 × 297 mm) is the standard in most of the world; Letter (8.5 × 11 in) is used in the US and Canada. Each image is scaled to fit its page without cropping and centred. With Auto orientation, landscape images get landscape pages.
Same as image makes each page the shape of its image, with no white bars, which suits screenshots and mixed sizes.
Keeping the PDF a reasonable size
With Original quality, JPG photos are embedded exactly as they are, so nothing is recompressed and the PDF is about as large as the photos together. Modern phone photos are often 3 to 6 MB each, so a ten-page PDF can reach 30 MB or more.
Smaller file shrinks each image to at most 2000 pixels on its longest side and saves it as a JPEG at 75% quality. That is plenty for reading on a screen and for printing on A4 or Letter at a normal size, and it usually cuts the file by a large factor.
Questions
Is PNG quality kept in the PDF?
Yes with Original quality, where PNGs are embedded losslessly. Smaller file converts pages to JPEG.
Can I paste screenshots instead of choosing files?
Yes. Copy an image and paste it on the page with Ctrl+V or Cmd+V when the drop area is showing.
Can I mix PNG and JPG in one PDF?
Yes. You can add images of different types and sizes and put them in any order.
Are my files uploaded anywhere?
No. The conversion runs in your browser and the page is not allowed to connect to other servers, so your files never leave your device.