Built for screenshots and line art
PNG is what screenshots, diagrams and exported charts usually are, and this wraps a set of them into one paginated document without changing the pixels. Nothing goes through a lossy step, so text in a screenshot stays as sharp in the PDF as it was in the image — which is the failure people usually hit when they route the same images through a JPEG step first.
Pages follow the order the files are listed in. Each is an A4 sheet turned to match its image and scaled to fit, so a batch of wide charts and tall screenshots stays legible without anything being cropped.
Transparency becomes white
A PDF page has no alpha channel in the way a PNG does, so anything transparent is composited onto a white background. For a screenshot or a chart that is exactly what you want; for a cut-out logo intended to sit on a coloured page it is worth knowing before you send the file.
For photographs, JPG to PDF produces a much smaller document. To extract the pages again later, use PDF to PNG, and Merge PDF will combine the result with other documents.