What happens when a browser converts a camera RAW file?

Your browser develops the camera’s sensor readings into a finished picture you can share. That copy is ready to use; the RAW remains your starting point for a different edit later.

FluffyBench · 5 min read · Reviewed October 15, 2026

What does a camera RAW file hold?

A camera RAW file starts with sensor readings. In a mosaic sensor, each spot records red, green or blue, like a tile in a single-color mosaic; developing the photo fills in the missing colors so every spot can show a full-color picture.

A generated DNG, before and after development

The marked patch crosses the same bright-to-dark edge on both sides. The colored tiles represent sensor readings; the finished picture has all three colors at each spot. How we reviewed

That’s the difference between RAW and a ready-to-view photo. With a camera JPG, the camera has already done the developing. RAW leaves that decision to software, so you can return to the readings and develop the picture differently later.

How does FluffyBench develop a RAW photo?

FluffyBench’s Camera RAW converter makes a finished picture with fixed development choices: the camera’s white balance, automatic brightness and 8-bit sRGB color. JPG or PNG encoding comes after that development.

Sensor mosaic, camera white-balance adjustment, estimation of missing colors, opaque 8-bit sRGB pixels, then JPG or PNG encoding. — White balance adjusts for the scene’s light. Filling in nearby colors is called demosaicing; sRGB is a common color space for screen pictures.

The development produces solid pixels with no see-through areas. The extra tonal precision in the RAW isn’t carried into those 8-bit pixels. Choosing a higher PNG sample depth later can’t bring the original sensor readings back.

With the default PNG settings and Size on Original, PNG keeps the developed pixels; JPG adds compression that changes them a little. Neither is a smaller RAW file: each is a newly encoded picture, and its size depends on the format and settings. There’s more on why an image file can grow when you convert it.

You don’t get RAW color-development controls in FluffyBench’s Settings. Those controls change the output after development. For the difference between sRGB and other screen colors, see our color-profile guide.

Why can a RAW preview differ from the saved picture?

FluffyBench normally previews the developed picture. When a full image would exceed the preview cache, it tries a JPEG thumbnail stored inside the RAW; that’s an already finished picture, so its appearance can differ from a fresh development.

Two possible preview paths, one full-conversion path

The thumbnail shortcut changes the preview path. Full conversion still uses the sensor readings, so judge the finished copy when it’s ready.

Doing it in FluffyBench

Use FluffyBench’s Camera RAW converter when you need a JPG or PNG you can open and share. Development and encoding happen in your browser; your photo stays on your device. Here’s a PNG conversion with the picture’s original dimensions.

Follow the controls from choosing a RAW photo to downloading the finished PNG.

Step 1. Choose a RAW photo from your device. The walkthrough uses a photo-derived DNG rendered for illustration.
1. Choose images opens your file picker.
Step 2. Use TO to choose PNG for a copy of the developed pixels, then open Settings.
1. Choose PNG in the TO format picker.
2. The gear opens Settings.
Step 3. Leave Size on Original to keep the developed picture’s pixel dimensions. Leave the other output settings at their defaults for this conversion.
1. Original keeps the pixel dimensions.
Step 4. Close Settings with the same gear, then choose Convert 1 to PNG.
1. Use the gear again to close Settings.
2. Convert 1 to PNG creates your finished copy.
Step 5. Check the saved format, size and picture, then choose Download. Open the copy where you’ll use it; keep your original RAW for a different development later.
1. Check the output dimensions and file size.
2. Check the developed PNG picture.
3. Download saves the PNG to your device.

Need a shareable JPG or PNG from your RAW photo?

FluffyBench Camera RAW converter

How we reviewed

Reviewed October 15, 2026

Current RAW conversion settings, generated-DNG checks and an earlier Sony ARW timing test, from the FluffyBench source and test records.

The sensor comparison uses the existing generated DNG and its actual developed PNG. The walkthrough uses a photo-derived DNG rendered for illustration, not a camera-fidelity test. The real-camera record is one Sony ARW from an earlier timing test.

Generated-DNG checks cover content, orientation and a damaged-file error. Exact browser versions and machine details were not retained. The comparison marks and enlarges the same source coordinates on the sensor mosaic and developed output; mosaic colors represent the filter color and reading strength.

In the earlier Sony ARW test, the source was about 31.8 MB and the PNG outputs were 64.5 MB and 59.9 MB, roughly twice the source size. There were 3 runs per browser. The record wasn’t repeated on the current build and has no exact source byte count, output-size variation, browser versions, machine details, timing ranges or fidelity comparison. These sizes describe that sample, not every RAW conversion.

There is no camera-model matrix, no output pair from a modern CR2, NEF or CR3 file, no numerical color-fidelity study, no 16-bit development comparison and no inventory of source and output metadata. The 8-bit sRGB setting and the orientation case don’t establish a color match with a camera JPG.

FluffyBench recognizes 23 RAW filename endings and checks the file signature. Recognizing an ending isn't a promise that every camera's files will decode. Known RAW markers can identify a file without its name; some TIFF-based variants use the filename to decide when markers are absent. TIFF without a RAW marker or RAW filename stays on the ordinary TIFF path.

Preview admission uses width times height times 4 bytes per pixel against the preview-cache threshold. Development uses LibRaw in a WebAssembly Worker, with 1 job at a time and a default 120 seconds timeout. That timeout is a code limit, not a typical decode time.