PNG to PDF

PNG is the right source for text and graphics

PNG uses lossless compression, which means every pixel in the file is exactly the pixel that was saved — nothing has been approximated away to save space. That property makes it the correct format for anything with hard edges and flat colour: screenshots, UI mockups, charts, diagrams, logos and text captured as an image. When these are embedded in a PDF, that sharpness carries through, so a screenshot of a spreadsheet remains legible when the reader zooms in. This is exactly where JPG struggles: its lossy compression smears the boundary between a black letter and a white background into a halo of grey speckles, which is why JPG screenshots look subtly dirty and PNG ones do not.

The transparency question

PNG supports an alpha channel — pixels can be fully or partially see-through — and PDF pages fundamentally are not transparent. Something has to be decided when the two meet. This converter composites transparent regions onto white, which matches how the image would look on a printed page or a normal document background. It is worth knowing because a logo designed to sit on a dark website will have been drawn in light colours with a transparent background, and it will therefore look almost invisible when placed on a white PDF page. If that happens, the fix is not the converter — it is to export a version of the graphic with the background colour baked in.