Editorial & Testing Policy

1. Primary sources only

Claims about file formats come from the standards that define them, not from other websites. Specifically:

• JFIF — ITU-T Recommendation T.871 (05/2011), also ISO/IEC 10918-5
• JPEG — ITU-T Recommendation T.81 (09/1992), also ISO/IEC 10918-1
• Exif — ITU-T Recommendation T.872, JEITA CP-3451
• PNG — W3C PNG Specification (Third Edition), ISO/IEC 15948
• WebP — RFC 9649
• PDF — ISO 32000-2
• Windows behaviour — Microsoft Learn documentation and reproduction on current Windows builds

Where a claim cannot be traced to a primary source, we say so in the text rather than asserting it.

2. Every converter is tested before publication

A conversion is not described as lossless unless we have confirmed it. Our test procedure for each converter:

1. Convert a set of reference images — a photograph, a screenshot containing small text, a flat-colour graphic, a greyscale scan, and a deliberately corrupted file.
2. For conversions claimed to be lossless, compare the source and output byte streams directly. "Lossless" on this site means byte-identical compressed data, not "looks the same".
3. For re-encoded conversions, decode both files and compare pixel data to confirm dimensions and colour are preserved.
4. Open every output in independent software — Windows Photos, macOS Preview, GIMP, Adobe Acrobat and Chrome — to confirm the file is genuinely valid and not merely accepted by the tool that made it.
5. Repeat in Chrome, Firefox, Safari and Edge, on Windows, macOS, iOS and Android.

3. Claims we refuse to make

Converter sites routinely publish things that are not true. We do not:

• We never say a conversion "improves quality" or "enhances" an image. No converter can restore detail that lossy compression discarded.
• We never describe a lossy conversion as lossless. JFIF to PNG preserves the pixels it is given, but the JPEG damage is already in those pixels — we say that on the page.
• We do not publish invented star ratings or review counts for our own tools, and there is no aggregateRating markup anywhere on this site.
• We do not publish user counts, conversion totals or testimonials we cannot substantiate.
• We do not use AI-generated text as published content without a human verifying every factual statement against a primary source.

4. Review schedule

Every page carries a visible "last reviewed" date, and that date only changes when the page has actually been re-checked. We do not refresh dates cosmetically to appear current — that is a practice Google explicitly discourages, and it destroys the value of the signal for readers.

Pages are reviewed when: a referenced specification is revised; browser behaviour changes in a way that affects the tools; a reader reports an error; or twelve months elapse, whichever comes first.

5. Corrections

If something here is wrong, we want to know, and we would rather hear it bluntly than not at all. Email [email protected].

Substantive corrections — anything that changes the meaning of a factual claim — are recorded in the changelog with the date and what changed. Typographical fixes are made silently.

6. Advertising and independence

The site is funded by display advertising. Advertisers have no input into anything published here, no advance sight of content, and no ability to request changes. We do not run sponsored posts, paid links, or affiliate recommendations, and we do not accept payment to appear in any comparison on this site.

Where we compare this site with other converters, we describe categories of behaviour rather than naming competitors, because their limits and policies change frequently and a dated comparison would be worse than none.

7. Use of AI tools

We use AI assistance for drafting and editing, as most publishers now do. It is not a substitute for verification: no factual claim is published on the basis of a model's output. Every specification reference on this site has been checked against the specification, and every converter behaviour has been reproduced by running it.