Executive Summary
Use JPG for Photographs (files are 10x smaller). Use PNG for Text Documents, Screenshots, and Signatures (crisp lines, transparency). This guide explains the technical difference between Lossy and Lossless compression.
You have a PDF. You need an Image. You go to convert it, and you are faced with a choice:
[ Download JPG ] or [ Download PNG ]
Does it matter? Yes. It matters a lot.
Choosing the wrong format can result in blurry text, massive file sizes, or even rejection from websites. This guide will explain the technical differences between the two titans of the image world, and tell you exactly which one to use for your specific document.
Understanding Compression: Lossy vs Lossless
The core difference lies in how they handle data "compression" (making the file smaller).
JPG (Joint Photographic Experts Group)
Type: Lossy Compression.
How it works: JPG assumes the human eye is imperfect. It looks at similar colors (like a blue sky) and deletes some of the subtle color variations to save space. Every time you save a JPG, it throws away a little bit of data.
The Result: Very small file sizes, but "Artifacts" (fuzzy noise) appear around sharp edges.
PNG (Portable Network Graphics)
Type: Lossless Compression.
How it works: PNG compresses data like a ZIP file. It shrinks the file size, but when you open it, it reconstructs every single pixel exactly as it was. It throws nothing away.
The Result: Perfect, crisp quality, but potentially larger file sizes.
Scenario 1: Converting a Resume / Contract (Text)
Winner: PNG
Text requires sharp edges. Black text on white paper is the highest possible contrast. If you use JPG, the compression will create gray "fuzz" around the letters. This makes small text hard to read.
Always use PNG for documents with text, lines, charts, or signatures.
Scenario 2: Converting a Flyer / Photo Album
Winner: JPG
If your PDF is full of photographs, gradients, and complex colors (like a marketing brochure), use JPG.
- A PNG of a full-page photo might be 10MB (too big to email).
- A JPG of the same photo might be 1MB (perfect).
The human eye cannot see the "loss" in a busy photograph, so the trade-off for smaller size is worth it.
Scenario 3: Transparency (Logos & Signatures)
Winner: PNG
This is the killer feature. JPG does not support transparency. If you try to save a logo or a signature as a JPG, the background becomes a solid white box.
PNG supports transparency (Alpha Channel). This allows you to have a signature that "floats" over other content. If you are using our Signature Tool, you MUST use PNG.
Scenario 4: The New Contenders (WebP & HEIC)
WebP (Google): The best of both worlds. Supports transparency AND high compression. Great for websites. Bad for compatibility (some older Outlook clients can't view it).
HEIC (Apple): The default iPhone format. It is incredibly efficient, but Windows often can't open it without a plugin. Avoid sending HEIC resumes.
Quick Decision Cheatsheet
| Content Type | Best Format | Why? |
|---|---|---|
| Text Documents | PNG | Sharp edges, easy to read. |
| Signatures | PNG | Transparency support. |
| Screenshots | PNG | Crisp UI elements. |
| Photographs | JPG | Small file size, good color. |
Conclusion
The file extension matters.
- For Lines and Letters (Docs, Signatures): Use PNG.
- For Light and Color (Photos): Use JPG.
Test it yourself. Upload your PDF to our Format Converter and download both versions to see the difference.