Lossy
A compression method that discards perceptually insignificant information to achieve substantial file size reduction. Original data cannot be perfectly reconstructed.
Lossy compression selectively discards information imperceptible to human vision, achieving far higher compression ratios than lossless methods. Once compressed, the original data cannot be recovered.
JPEG uses Discrete Cosine Transform (DCT) to convert to frequency domain, then quantizes high-frequency components (fine details). WebP and AVIF employ advanced predictive coding, producing 25-50% smaller files than JPEG at equivalent quality.
A quality parameter (typically 1-100) controls compression strength. Quality 80 is the standard web delivery setting, balancing file size and visual fidelity. The image compression tool allows real-time quality adjustment with preview. Repeated save cycles cause cumulative "generation loss" that must be considered in editing workflows.