Image Format Comparison: JPEG vs PNG vs WebP vs AVIF — Quality, Size, and SEO

Major Image Format Comparison

When uploading images to the web, which format should you choose? Honestly, your format choice alone can determine your page loading speed and Core Web Vitals score.

JPEG — A Trusted Classic

Born in 1992, JPEG remains the most widely used web image format. It is ideal for photographs and images with complex color gradients. However, it is not suitable for logos or images requiring sharp text — JPEG does not support transparency.

Compression Quality Guide:

• Web optimization: 75–85% quality
• Thumbnails: 60–70% quality
• Print: 95%+ quality

PNG — King of Transparency

PNG supports lossless compression and is the go-to format when transparency is required — logos, icons, and UI screenshots. Its main drawback is large file size; for photographs, PNG is rarely necessary or appropriate.

WebP — Google's Answer

WebP is a next-generation format developed by Google. The key advantage: it delivers similar quality to JPEG at 25–35% smaller file sizes. It also supports animation, making it suitable for dynamic images.

Real-world file size comparison (1920×1080 photo):

• JPEG at 80%: ~450 KB
• WebP at 80%: ~290 KB (35% reduction)
• AVIF at 80%: ~190 KB (57% reduction)

WebP is already supported by the vast majority of browsers as of 2023.

AVIF — The Cutting Edge

AVIF applies the AV1 video codec to still images, achieving even better compression than WebP. The tradeoff is longer encoding times, which can be burdensome for real-time conversion pipelines.

Browser support: Chrome 85+, Firefox 93+, Safari 16+. As of 2024, approximately 92% of browsers support AVIF.

Image Formats and SEO

Image file weight directly affects your LCP (Largest Contentful Paint) score under Core Web Vitals.

Conclusion

As of 2026, WebP or AVIF should be your default for all new web images. Converting existing JPEG or PNG images will immediately improve your page loading speed — and your search rankings with it.