Format
PNG, every pixel exactly as it was.
A PNG stores a picture without losing anything, and it can have see-through areas. That makes it the format for screenshots, logos and anything with sharp edges.
Flex Convert reads PNG and writes it, and keeps transparency when it converts a PNG to another format that can hold it.
Facts
The record.
Extension
.png.
Compression
Lossless: the picture decodes to exactly the pixels that went in.
Transparency
A full alpha channel, so edges and shadows fade smoothly instead of ending in a hard line.
Colour
Up to 16 bits per channel, or a small palette for simple graphics.
Animation
Not in the basic format. An extension called APNG adds it and is not covered here.
In Flex Convert
Read and written. Colour is converted to sRGB.
Measured examples
What we measured.
Four generated pictures, converted from PNG to WebP on this site.
| Test file | Size | Change | Time | Result |
|---|---|---|---|---|
| Transparent logo, 2048 by 2048Chrome | 82 kB → 42 kB | 49 percent smaller | 360 ms | 46.1 dB likeness · 2048 × 2048 · Transparency kept |
| Detailed photo, 12 MPChrome | 22 MB → 1 MB | 95 percent smaller | 1.1 s | 32.9 dB likeness · 4000 × 3000 |
| App screenshot, 2400 by 1600Chrome | 162 kB → 61 kB | 62 percent smaller | 250 ms | 47.1 dB likeness · 2400 × 1600 |
Measured on November 7, 2026 in Google Chrome 157, on Apple M1 Pro. Times run from pressing Convert to the result being ready, with the page already loaded. Likeness is PSNR against the original: higher is closer, and above 40 dB the difference is hard to see. Every test file was generated for these measurements, none is anyone else's work, and each is described on the About page.
The 12-megapixel detailed photo was 22 MB as a PNG and 1 MB as a WebP, 95 percent smaller. The app screenshot went from 162 kB to 61 kB, and the transparent logo from 82 kB to 42 kB with its transparency intact.
Good to know
The trade PNG makes.
Everything exact, at the price of size.
Why PNG files are large
A PNG cannot approximate. For a photograph, every grain of noise has to be stored exactly, and the file balloons: our generated 12-megapixel photo was 22 MB. For flat graphics the same method is very efficient, which is why screenshots and logos are small.
Where PNG is the right answer
Text, interface screenshots, diagrams and pixel art stay crisp. A picture you will edit repeatedly should live as PNG, because nothing is lost between saves. Transparent logos need it unless the destination accepts WebP or AVIF.
Where it is not
A photograph as PNG is often ten or twenty times larger than the same picture as JPG or WebP with no gain anyone can see. Convert photographs to a lossy format for sharing.
Choosing
When to pick it, and when not to.
A format is a trade. These are the trades this one makes.
Keep PNG when
the picture has text, thin lines or transparency, or you will edit it again.
Convert to WebP when
the picture goes on a web page. It keeps transparency and is far smaller.
Convert to JPG when
it is a photograph without transparency going somewhere that accepts only JPG.