The Fundamental Difference
JPG uses lossy compression — it achieves small file sizes by discarding image data the algorithm predicts the human eye won't notice. PNG uses lossless compression — every pixel is preserved exactly. This single difference determines which format is better for any given image.
The rule of thumb: photographs = JPG, graphics = PNG. But real-world cases are more nuanced.
Use JPG When:
- The image is a photograph — real-world scenes, portraits, landscapes, products on complex backgrounds. JPG's lossy compression is optimised for these types of images and produces excellent results with small file sizes.
- File size is the priority — JPG will always be significantly smaller than PNG for photographic content. A 1200×800 portrait photo might be 150 KB as JPG vs 2.5 MB as PNG.
- You don't need transparency — JPG doesn't support transparent backgrounds. If you're placing an image on a solid colour background that matches the image background, JPG is fine.
- You won't re-save the file multiple times — Each time a JPG is saved, it's re-compressed and quality degrades slightly. If you're doing a final export, JPG is appropriate.
Use PNG When:
- You need a transparent background — Logos, icons, product photos on transparent backgrounds, UI elements. Only PNG (and WEBP) supports full alpha transparency.
- The image contains text or sharp lines — JPG compression creates visible artefacts around high-contrast edges. Screenshots, diagrams, and graphics with text look much better as PNG.
- You'll edit and re-save the file multiple times — PNG is lossless, so repeated saves don't degrade quality. Use PNG for your working source files; export to JPG only for the final version.
- The image is a logo or icon — Logos require sharp, artifact-free edges and transparent backgrounds. PNG is the correct format.
- Exact colour accuracy is critical — Technical diagrams, colour swatches, and medical images where precise colour values matter should use PNG.
Quick Reference Table
| Image Type | Best Format | Reason |
|---|---|---|
| Portrait photograph | JPG | Small file, excellent quality for photos |
| Product on white background | JPG | No transparency needed, small file |
| Product on transparent background | PNG | Needs transparency |
| Company logo | PNG (or SVG) | Needs transparency + sharp edges |
| Screenshot of website/app | PNG | Sharp text requires lossless |
| Infographic | PNG | Contains text and graphics |
| Social media photo | JPG | Photograph; small file preferred |
| Button / UI element | PNG or SVG | Transparency + crisp edges |
What About WEBP?
WEBP supports both lossy compression (better than JPG) and lossless compression with transparency (smaller than PNG). If browser compatibility allows, WEBP is the better choice in both scenarios. Convert any image to WEBP using our free WEBP Converter.
Convert Between Formats
If you have a PNG that should be JPG, or a JPG that needs transparency as PNG, use our free converters:
- JPG to PNG Converter — Add transparency support
- PNG to JPG Converter — Reduce file size for photographs