Why lossless matters for PNG
PNG files are usually screenshots, charts, diagrams or exported designs: images with sharp edges, flat colours and small text. Many converters quietly re-save every image as JPEG inside the PDF, which adds a faint grey haze around letters and lines. Here, Lossless pages is ticked by default on PNG files, so the PDF holds your images exactly as they are.
The trade-off is size. A full-screen screenshot is typically 300 KB to 1 MB as a lossless page, versus 150 to 300 KB as JPEG. If you are sending photos rather than screenshots, untick it and use the JPEG quality slider instead.
Page size
- Fit image makes each page the shape of its image, with no border. Best for reading on screen.
- A4, Letter or Legal places each image on a standard sheet with an 8 mm margin, scaled to fit. Use it if the PDF will be printed or uploaded to a portal that expects document pages. Images are placed at 150 DPI, so very large screenshots are scaled down to fit the page.
Transparent PNGs
Transparent areas show as white in PDF viewers, the same as the paper. If a logo with white lettering disappears, place it on a coloured background first.
Questions
Can I mix PNG and JPG files?
Yes. Tick Allow all image types to add JPG, WebP, HEIC and others to the same PDF. For a batch of photos, the JPG to PDF page has more relevant defaults.
Can the PDF be searched?
No. The pages are images, so text in your screenshots can be read but not searched or copied without OCR software.