Converting PNG images to a PDF bundles them into a single portable document. Screenshots become a sharable report; diagrams become a presentation-ready document; scanned pages become a combined archive. Each PNG becomes one page in the output PDF.
PNG vs JPEG as input
PNG files are lossless — they preserve every pixel exactly. When you embed a PNG in a PDF, the quality in the output matches the quality in the source exactly. For screenshots, technical diagrams, and line art, PNG is the appropriate source format.
JPEG files use lossy compression that introduces visible artifacts around high-contrast edges. If you already have JPEGs, the JPG to PDF tool handles them; PNG to PDF is optimized for lossless source images.
On-device processing
The conversion runs entirely in your browser using pdf-lib. Each PNG image is embedded in the PDF at its native resolution. No upload occurs — the images are read from your device, the PDF is built locally, and the result is downloaded directly to you.
PNG and PDF: when each is the right format
PNG is a raster image format designed for screen display, digital archiving, and situations where lossless compression matters: screenshots, diagrams, logos, and medical images. PDF is a fixed-layout document format designed for print and sharing across different systems. Converting PNG to PDF is the right move when you need to share an image as a document, print it at a consistent size, or combine it with other pages in a larger document.
A single PNG converted to PDF becomes a one-page document at the native pixel dimensions of the image. Multiple PNGs converted and merged become a multi-page document. The output is identical to the original image: PNG is lossless, and the conversion preserves every pixel.
Page size and image scaling
By default, the PNG to PDF tool places each image on a page sized to match the image's native pixel dimensions, using the image's embedded DPI value to set the physical page size. A 1240x1754 pixel PNG at 150 DPI produces an A4-sized page. If no DPI is embedded, a sensible default is applied.
If you need to output at a specific page size (A4, US Letter), convert the PNG to PDF and then use a PDF editor or the Crop PDF tool to adjust the page dimensions.
Combining multiple images
To combine several PNG images into one PDF, the most direct route is: convert each PNG to PDF individually (each becomes a single page), then use Merge PDF to combine them in order. The output is a multi-page PDF where each page is one original image.