I Benchmarked 17 Image Conversions on My Production Server. Some Results Were Not What I Expected.

Short summary

Author benchmarked 17 image format conversions on 50 real production images and found common wisdom fails: HEIC to JPG increases file sizes 14%, AVIF delivers only 10% additional compression vs WebP but encodes 7x slower, and higher-DPI PNG paradoxically yields smaller files due to better gradient prediction. Recommendations: use WebP for most websites, AVIF when time is not a constraint, and skip HEIC-to-JPG entirely.

• •HEIC to JPG increases file sizes 14%, not decreases—HEIC uses a superior codec
• •AVIF provides only 10% better compression than WebP but takes 7x longer to encode
• •Higher-DPI PNG renders smaller files due to smoother gradients compressing better

Generated with AI, which can make mistakes.