PNG compression works by removing unnecessary metadata and optimizing the image data structure. A PNG shrinker can compress PNG files using either lossless compression (keeps 100% quality) or lossy compression (reduces file size more by removing some visual data). Modern PNG compression tools analyze pixel patterns to reduce redundancy while maintaining image clarity.

Compressed PNG files load faster on websites, use less storage space, and are easier to share via email. Large PNG files slow down page speed and consume bandwidth. Using a PNG shrinker to compress PNG images can reduce file sizes by 50-80% without visible quality loss, making them perfect for web use, presentations, and social media.

Online PNG compression requires uploading files to external servers, risking privacy and requiring internet connection. Offline PNG shrinker tools like TinyFast compress PNG files directly on your Mac - faster, more secure, and work without internet. Offline compression keeps confidential files private and uses hardware acceleration for instant results, while online compressors are slower and expose your data.

It depends on the compression method. Lossless PNG compression reduces file size without any quality loss - the image looks identical. Lossy PNG compression removes some visual data to achieve smaller sizes, but with modern PNG shrinker tools, the quality difference is barely noticeable. Most users can compress PNG files by 60-70% with zero visible quality reduction using smart compression algorithms.

Lossless PNG compression preserves 100% of image quality by optimizing data structure - perfect for graphics, logos, and screenshots where precision matters. Lossy PNG compression achieves 50-90% smaller file sizes by removing imperceptible visual data - ideal for photos and web images.