# PNG to WebP when it comes out lighter.

> Turn a PNG into a WebP with As WebP in Smally for Mac, shown only when it comes out lighter than the PNG copy. The browser tool compresses PNG files in your tab.

- URL: https://meetsmally.com/png-to-webp/
- Language: en
- Spanish version: https://meetsmally.com/es/png-a-webp/
- Site map for assistants: https://meetsmally.com/llms.txt

For some PNGs, Smally for Mac offers As WebP: a WebP copy that is shown only when it comes out lighter than the PNG copy. The drop zone below compresses PNG files in this tab.

## How it works

1. **Drag your file in.** Drop your file on the drop zone above, or choose it with the file picker. Nothing is uploaded.
2. **Compare the original and the copy.** Press Preview on the finished row, drag the divider between the original and the copy, and look at it at 100 % or 200 %.
3. **Download the lighter copy.** Download the copy you like. Your original stays untouched, and a copy is offered only when it is lighter.

## Two ways to lighten a PNG

In the browser, Smally repacks the PNG losslessly with oxipng and also tries a 256-colour palette copy, then offers the lighter file. It stays a PNG, with its transparency.

In Smally for Mac the same PNG gets its PNG copy first, and for some PNGs the preview also offers As WebP, a different format that is shown only when it comes out lighter than the PNG copy.

## When you see As WebP

- When a lossy route made the lighter result for your PNG.
- When the PNG copy kept most of its bytes, as photographs saved as PNG often do.
- When no PNG copy came out lighter at all.

## WebP or PNG?

A PNG is lossless, so every pixel is the same as the original. A WebP copy is a different format and can differ from the PNG pixel by pixel, which is why Preview lets you compare it with the original before you keep it.

Browsers open WebP, but some older programs do not, so keep the PNG when a file has to open everywhere.

## What stays the same

- Your original PNG. Smally never changes it; the copy is saved as a new file next to it, named like logo-smally.webp.
- Your privacy. The browser copy is made in this tab and the Mac copy on your Mac. Your files are never uploaded.

## Quick facts

| This kind of file | Smally in the browser | Smally for Mac |
| --- | --- | --- |
| What it takes | PNG, up to about 24 megapixels | PNG, up to 40 megapixels |
| What it makes | A PNG copy: a PNG stays a PNG | A PNG copy first; for some PNGs, As WebP when it comes out lighter |
| What stays | Transparency; the original is never changed | The original PNG is never changed |
| Per batch | Up to 5 files at a time, 50 MB each, with Download All as one zip | Up to 50 files at a time |
| Where it is processed | In this tab, on your device. Nothing is uploaded | On your Mac. Nothing is uploaded |
| When the original is kept | A copy would not be at least 1% lighter | A copy would not be at least 1% lighter |

## Questions

- **Does Smally turn every PNG into a WebP?** No. As WebP is offered for some PNGs, and only when the WebP comes out lighter than the PNG copy.
- **Can I convert PNG to WebP in the browser?** No. The browser version keeps each file in its own format: a PNG stays a PNG and a WebP stays a WebP. As WebP is in Smally for Mac.
- **Why do I not see As WebP on my PNG?** It is shown only when a WebP copy comes out lighter than the PNG copy. For some PNGs there is no such copy.
- **Is my PNG uploaded anywhere?** No. The browser copy is made in this tab, on your device, and Smally for Mac works on your Mac. Your files never leave your device.

## More

- [Compress PNG](https://meetsmally.com/compress-png/)
- [Compress WebP](https://meetsmally.com/compress-webp/)
- [Compress AVIF](https://meetsmally.com/compress-avif/)

---

Smally in the browser. Smally for Mac 0.16.0 (build 35, beta) needs Apple silicon and macOS 26 or later; download: https://downloads.meetsmally.com/latest. Files are never uploaded. Source of truth: https://meetsmally.com/png-to-webp/