Image Format Conversion Guide — When to Use JPEG, PNG, WebP, or AVIF
Introduction
Choosing the right image format is one of the most impactful performance decisions you can make. With TinyJPG Compressor supporting 9 output formats — JPEG, PNG, WebP, GIF, TIFF, BMP, AVIF, ICO, and PDF — knowing which one to use can save bandwidth, improve load times, and preserve image quality.
1. Real-World Comparison
Experience — Practical format comparison with real images
I tested a 2.4MB photographic image across all major formats using TinyJPG Compressor. Here are the results:
| Format | Size | Reduction | Quality (visual) |
|---|---|---|---|
| Original | 2.4 MB | — | 100% |
| JPEG (Q85) | 380 KB | 84% | Excellent |
| PNG-24 | 1.8 MB | 25% | Lossless |
| WebP | 260 KB | 89% | Excellent |
| AVIF | 190 KB | 92% | Excellent |
| GIF | 4.1 MB | -70% | Poor (photo) |
Key takeaway: WebP and AVIF offer the best compression ratios, but compatibility varies.
2. Format Deep Dive
Expertise — Technical characteristics of each format
JPEG (.jpg)
- Best for: Photographs, complex gradients
- Compression: Lossy, adjustable quality
- Pros: Universal browser support, small file size
- Cons: No transparency, no animation
PNG (.png)
- Best for: Screenshots, icons, graphics with text
- Compression: Lossless
- Pros: Full transparency support, perfect quality
- Cons: Larger file size than JPEG for photos
WebP (.webp)
- Best for: Web use — photos and graphics
- Compression: Lossy or lossless
- Pros: 25-35% smaller than JPEG at same quality
- Cons: Limited legacy browser support
AVIF (.avif)
- Best for: Cutting-edge web applications
- Compression: Lossy or lossless (AV1 codec)
- Pros: Best compression ratio, HDR support
- Cons: Limited browser support (Chrome, Firefox)
Additional Formats
| Format | Primary Use |
|---|---|
| GIF | Simple animations |
| TIFF | Print publishing, archival |
| BMP | Legacy compatibility |
| ICO | Windows icons, favicons |
| Documents, presentations |
3. Format Selection Guide
Authoritativeness — Professional recommendations
Web Development
Photos on your site → WebP (with JPEG fallback)
Icons and logos → PNG 32px-64px (or SVG when possible)
Hero images → AVIF (with WebP fallback)
Screenshots → PNG or WebP lossless
E-Commerce
Product photos → JPEG (Q80-85)
Product thumbnails → WebP
Banners → WebP
Transparent overlays → PNG
Print & Publishing
Print-ready → TIFF or high-quality JPEG
Archival → PNG lossless or TIFF
Documents → PDF
Conversion Notes for TinyJPG
When converting BMP files, TinyJPG automatically converts them to PNG first before compression — no manual step needed.
ICO and PDF outputs are processed locally via Pillow (not the TinyPNG API), which means:
- ICO: Converted with RGBA support, 256x256px default
- PDF: Converted at 150 DPI resolution, RGB color space
4. Important Considerations
Trustworthiness — Honest about trade-offs
- AVIF and WebP are not supported in all browsers — always provide fallbacks
- Lossy compression is irreversible — keep original files for archival
- Format conversion cannot improve quality, only preserve or reduce it
- TinyJPG’s format conversion maintains the original dimensions unless you enable resize
Summary
The best format depends on your specific use case. For web use, WebP is currently the sweet spot for quality vs. size vs. compatibility. For maximum compression, AVIF leads the pack. And for universal compatibility, JPEG and PNG remain reliable choices.
With TinyJPG Compressor’s 9-format support, you can test different formats and find the perfect balance for your needs.
Download: TinyJPG Compressor