Image tool

Grayscale Image

Convert a colour image to true single-channel greyscale, using luminance weighting rather than a flat channel average.

Image PNG
PrivConvert
Privacy-first conversion
No files stored
In-memory processing
Deleted instantly
No sign-up needed

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How to Convert Image to PNG Online

You can convert Image to PNG right in your browser in under a minute. Your file is processed privately in memory and deleted the instant the PNG is ready.

1
Upload your Image file

Drag and drop your file into the upload area, click to browse your device, or paste a URL to a file hosted online. You can upload files up to 250 MB and batch convert up to 20 files at once.

2
Automatic conversion

Once uploaded, the conversion from Image to PNG starts automatically. The process runs entirely in an isolated environment - your data never leaves the secure pipeline.

3
Download your PNG file

Your converted file is ready instantly. Click the download button to save it to your device. The file is deleted from memory immediately after download.

Private by design, not as an afterthought

Most online converters upload your files to a server, keep them for days, and may mine them for AI training or resale. PrivConvert was built the opposite way - around your privacy.

Fast in-memory processing

Each job runs in an isolated in-memory sandbox, so most conversions finish in seconds instead of waiting in a queue.

Nothing is stored

We never keep a copy. Once your PNG is delivered, both the original and the result are gone - there is nothing left to leak or misuse.

Isolated sandbox

Every conversion runs in its own locked-down process with no network access, so files can never leak or interfere with one another.

No human ever sees it

Your files are handled entirely by automated code. No staff, partner or AI model ever reads, stores or trains on your data.

Image vs PNG - Format Comparison

FeatureImagePNG
File extension.image.png
Supported by PrivConvertYes (as input)Yes (as output)
Privacy-safe conversionIn-memory, zero storage
Max file size250 MB per file
Batch supportUp to 20 files simultaneously

A converter you do not have to worry about

PrivConvert handles thousands of conversions every day for developers, designers and privacy-conscious people who need a image converted without handing over a permanent copy.

250 MB Max file size
450+ Conversion tools
0 sec File retention
100% Free to use

Frequently Asked Questions

Is this the same as removing saturation?
The visible result is similar but the file is not. Desaturating in an editor usually leaves three identical colour channels behind, whereas this produces a genuine single-channel greyscale image - typically about a third the pixel data, since there is one value per pixel instead of three.
How is the grey value calculated?
By luminance weighting, which reflects how human vision actually works: green contributes most to perceived brightness, red less, blue least. Averaging the three channels equally would render a bright red and a bright blue as the same grey even though the eye sees them very differently.
Can I get the colour back afterwards?
No. Discarding colour is irreversible - three channels are collapsed into one and the hue information is gone. Keep your original if you might need the colour version again.
What happens to a transparent background?
Transparency is not preserved by the greyscale conversion, so a transparent background becomes solid. If you need both greyscale and transparency, apply the greyscale step in an editor that keeps the alpha channel.
Is my image kept private?
Yes. The conversion runs entirely in memory in an isolated process. Your image never touches disk and is deleted the instant your download is ready.

Related Tools

Image to AVIF Image to Base64 PNG to JPG PNG to WebP PNG to ICO JPG to AVIF

Further Reading

PNG vs JPG: Which Image Format Should You Use? Image Formats Compared: JPEG, PNG, WebP, AVIF, and More