Image compression tools

What you need to know

Image compression reduces file size by eliminating redundant or less-visible pixel data. Lossless compression preserves every pixel while finding more efficient encoding patterns, typically achieving 10-30 percent size reduction for PNG files. Lossy compression discards subtle color and detail information that the human eye is less likely to notice, achieving 50-90 percent size reduction for photographic images. The key to effective compression is balancing file size against visual quality: too little compression wastes bandwidth and storage, while too much compression introduces visible artifacts, banding, and blurriness that undermine the image purpose.

Key points

• JPG quality 80-85 is the standard sweet spot for web photos, balancing size and fidelity
• PNG cannot be made significantly smaller through quality settings; converting to WebP or JPG is more effective
• Compression artifacts are most visible around sharp edges, text, and areas of flat color
• Resizing an image before compression often produces better results than compressing at full resolution
• WebP typically produces files 25-35 percent smaller than equivalent-quality JPG

Reducing email attachment size

Most email providers limit attachments to 25MB. A single high-resolution photo from a modern camera can exceed 10MB. Compressing to quality 80 JPG typically reduces a 10MB photo to under 1MB, making it easy to email without cloud file sharing links.

Optimizing website images for Core Web Vitals

Smaller, properly compressed images speed up Largest Contentful Paint and reduce data transfer. Compressing hero and content images before upload is one of the highest-impact steps for meeting Core Web Vitals thresholds.

Recommended practices

• Start with quality 80 and adjust downward only if the file is still too large
• Compress as the final step after all resizing, cropping, and editing are complete
• Use WebP for web delivery when browser support allows, with JPG as a fallback
• Compare the compressed output side by side with the original before finalizing
• For text-heavy screenshots, use PNG or WebP lossless rather than JPG to avoid blurry text

Common mistakes to avoid

• Compressing already-compressed images repeatedly: Re-saving a JPG at lower quality multiple times compounds artifacts. Always compress from the original high-quality source, not from a previously compressed version.
• Using maximum quality 100 for web images: Quality 100 JPG files are often 2-3 times larger than quality 90 files with no visible difference. The file size penalty far outweighs any quality gain for web use.
• Compressing PNG files with JPG-style quality sliders: PNG is lossless and does not have meaningful quality levels. If a PNG is too large, convert it to WebP or JPG rather than expecting PNG compression to produce dramatic size reductions.