Compression vs format change
TinyPNG is 'same format, fewer bytes'. WebP is 'better format, fewer bytes'. You can TinyPNG a PNG and still fail Lighthouse's next-gen audit.
Why it matters
- Privacy and NDA work.
- Lighthouse next-gen audit.
- Batch UX without a monthly TinyPNG plan.
How to do it
- If you must keep PNG (legacy email), TinyPNG is fine.
- For websites, convert to WebP instead.
- Do not TinyPNG and then smash quality again.