OUTPUT SETTINGS
Quality, lossless mode, and Skip larger outputs
Each setting solves a different problem: quality controls a lossy-encoding tradeoff, lossless targets reversible pixels, and Skip larger outputs avoids writing uneconomical candidates to disk.
Key points
- Quality and lossless mode are independent settings, not substitutes.
- Lossless output does not guarantee a smaller result; Skip larger outputs avoids wasteful writes.
- For a lossy source such as JPEG, a lossless container cannot restore removed detail.
Quality: set the lossy-output tradeoff
Quality controls a tradeoff for lossy output. It is not a comparable grade across formats and it is not true lossless. Choose it against real material and the actual delivery environment rather than one isolated number.
When continuing from JPEG into another lossy output, visible extra loss depends on image content and settings. Testing a small representative set is more reliable.
Lossless: choose it for reversible pixels
Lossless mode aims for reversible decoded pixels. Use it when pixel identity matters more than file size, while accepting that the result may not be smaller than the source.
Writing a lossy source such as JPEG to lossless AVIF or WebP only preserves the pixels currently decoded from JPEG; it cannot restore information removed by earlier compression.
Skip larger outputs: avoid pointless replacement
When a candidate output is the same size as or larger than the source, enabling this option can leave it unwritten. It is especially useful for lossless re-encoding or material that has already been optimized.
It is not a compression-rate promise. Source content, target format, and encoding choices still determine whether a candidate is smaller.
Common questions
What is the difference between quality 100 and lossless mode?
Quality 100 is still a quality setting. Lossless mode is the encoding choice for reversible pixels; they are not the same.
Why was a lossless output skipped?
The candidate may not have been smaller than the source. With Skip larger outputs enabled, the app can leave it unwritten.
Can lossless AVIF recover JPEG detail?
No. Information removed by earlier lossy JPEG encoding cannot be restored by changing to a lossless container.