PDF, PNG, and JPEG are three of the most common file formats, and people use them interchangeably without thinking about which is appropriate. Each format has specific strengths and weaknesses. Using the wrong format wastes file size, reduces quality, or causes compatibility issues.
What Is a PDF?
PDF (Portable Document Format) is a document format, not an image format. It is designed to contain pages of content — text, images, tables, and graphics — in a fixed, printable layout. PDFs can contain multiple pages, embedded fonts, hyperlinks, and form fields. They look identical on every device and operating system. PDFs are the standard for documents — contracts, reports, manuals, invoices, and anything that needs to be read, signed, or printed.
What Is a JPEG?
JPEG (also JPG) is a raster image format optimized for photographs and complex color gradients. It uses lossy compression — removing some image data to achieve very small file sizes. A high-quality photograph that would be 10 MB as a raw file compresses to 500 KB as a JPEG with barely visible quality loss. The trade-off: JPEG is not good for images with sharp edges (text, logos, line art) — compression artifacts make edges look blurry. JPEG does not support transparency.
What Is a PNG?
PNG (Portable Network Graphics) is a raster image format that uses lossless compression. Every pixel is preserved exactly — there is no quality loss from compression. PNG is ideal for images with text, logos, screenshots, and graphics with sharp edges. It supports transparency (transparent backgrounds). The trade-off: PNG files are larger than JPEG for photographs. A 500 KB JPEG photograph might be 3–5 MB as PNG.
When to Use PDF
Multi-page documents: Anything with more than one page belongs in PDF — reports, manuals, brochures, presentations for download. Documents to be signed: PDF is the universal standard for e-signatures and digital signing. Print-ready files: PDFs embed fonts and ensure consistent print output. Official records: Contracts, invoices, certificates, and government forms. Web content for download: Guides, whitepapers, and resources shared as downloadable files.
When to Use JPEG
Photographs: Product photos, event photos, profile pictures — anything photographic. Web images: Blog post images, banner ads, social media images (where small file size matters more than pixel-perfect quality). Email inline images: Small JPEG files load quickly in email clients. Camera output: Most cameras and phones save photos as JPEG by default — usually the right choice. Do NOT use JPEG for: logos, text-heavy graphics, screenshots, or anything requiring transparency.
When to Use PNG
Logos: Always save logos as PNG — the sharp edges and potential transparency need lossless format. Screenshots: Screenshots contain text and sharp UI elements — PNG preserves them crisp. Icons and graphics: Any graphic with text or geometric shapes belongs in PNG. Transparent backgrounds: PNG supports transparency; JPEG does not. Web graphics: Charts, diagrams, and infographics with text benefit from PNG's sharpness. Do NOT use PNG for: full-color photographs (too large) unless you specifically need lossless quality.
Quick Reference Guide
Document with text (report, invoice, contract) → PDF. Photograph for web → JPEG. Logo with transparent background → PNG. Screenshot → PNG. Product image for e-commerce → JPEG. Printable brochure → PDF. Icon for a website → PNG. Profile picture for social media → JPEG. Presentation slides for download → PDF. Infographic with text and charts → PNG (or PDF for better scalability).
Frequently Asked Questions
Should I save my logo as PDF, PNG, or JPEG?
PNG is the correct format for logos — it preserves sharp edges and supports transparent backgrounds. For print, SVG or PDF with vector graphics is even better.
Can I convert a PNG to PDF?
Yes. In Windows, open the PNG in Photos and print to PDF. On Mac, open in Preview and export as PDF. Online tools can also convert images to PDF.
Is JPEG or PNG better for websites?
JPEG for photographs (smaller files). PNG for graphics, logos, and screenshots (better quality for non-photographic content). WebP (a modern format) is better than both for most web use cases.
Can a PDF contain JPEG images?
Yes. PDFs often embed JPEG images within them, especially in brochures and photo-heavy documents. The PDF container holds the images along with text and layout information.