When you need to turn an image into a PDF, you often have a choice: use a JPG (JPEG) or a PNG version of the image. Most of the time it does not matter. Sometimes it matters a lot. Here is when to use each format, and what changes about the resulting PDF.
What JPG and PNG do differently
JPG uses lossy compression. Each time an image is saved as JPG, the encoder discards some pixel data that it judges to be imperceptible. The result is a smaller file. Compression artifacts are usually invisible at normal viewing distances but become visible when you zoom in closely or print at large scale.
PNG uses lossless compression. Every pixel is preserved exactly. PNG files are larger, but the image looks identical to the original at any zoom level and does not degrade when re-saved.
File size in the resulting PDF
When you convert an image to PDF, the image data is embedded inside the PDF container. A JPG-source PDF embeds a JPEG stream and will be approximately the same size as the source JPG file. A PNG-source PDF embeds a losslessly-compressed image and will typically be significantly larger for the same visual content.
A photograph converted from JPG typically produces a PDF of 1–3 MB. The same photograph converted from a PNG source might produce a PDF of 8–25 MB, depending on dimensions and colour depth.
For photographs, JPG is almost always the better choice if file size matters.
When PNG produces a better result
PNG is the better source format when your image contains:
- Transparency. JPG does not support transparent pixels - a transparent background becomes white (or another solid fill). PNG preserves transparency exactly, which matters for logos, icons, and watermarks placed over other content.
- Text, lines, or sharp edges. JPG compression creates ringing artifacts around high-contrast edges - the kind found in screenshots, diagrams, charts, and images that contain readable text. PNG keeps those edges pixel-perfect.
- Flat colours and solid fills. Logos, icons, and illustrations with solid colour blocks compress very efficiently as PNG with no quality loss. JPG introduces noise into flat-colour areas that is visible on close inspection.
Practical guide
Use JPG when you are converting
- Photographs or realistic artwork
- Scanned documents (no transparency)
- Anything where keeping the PDF size small is the priority
Use PNG when you are converting
- Screenshots or screen recordings
- Diagrams, charts, and graphs with text labels
- Logos or brand assets that must stay sharp at any scale
- Images with transparent backgrounds
- Any image destined for professional printing
Converting images to PDF with Pagivo
Pagivo's Image to PDF tool accepts both JPG and PNG files. You can mix formats in a single conversion - for example, photograph JPGs with a PNG logo page into one PDF. Upload your files, arrange the page order in the workspace if needed, and download.
Does compressing the PDF afterwards even things out?
Partially. Running a PNG-sourced PDF through a compression tool reduces its size significantly, because the compressor re-encodes the embedded images using lossy JPEG compression. A JPG-sourced PDF has less room for further compression because the images are already lossy-compressed - further compression either does little or degrades quality. If you plan to compress the PDF after conversion, starting with JPG sources still produces the best result.