Lossless vs lossy compression in 5 minutes

Every compression algorithm in the world falls into one of two camps: lossless (keeps every bit) and lossy (throws some away).

Why this matters today

Lossless is for source files you'll keep editing. Lossy is for finals shipped to the world. Mixing them up is how you end up with a 200 MB invoice.

A lossy file is a delivery, not an archive.

In practice

Here is the part that turns theory into a habit:

• Start small — a single file, a single page, a single test.
• Measure twice. Trust the numbers, not the vibe.
• Keep an undo path. Reversible decisions buy you courage.

A note on tooling

Every tool on this site runs in your browser unless we say otherwise. That changes the trade-offs: nothing to upload, nothing to retain, nothing to leak. The downside is a small ceiling on file size and a dependency on your device's CPU — both acceptable for most editorial workflows.

Takeaway

Edit in lossless, deliver in lossy, and never the reverse.