Data URI to PNG Converter

Strips the data: URI scheme prefix if present, decodes the remaining base64 text back into raw bytes, and verifies the result starts with a valid PNG file signature before offering it for download, all client-side. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-07-26

Overview

Introduction

Sometimes all you have is a data: URI string — copied from a stylesheet, an API response, or DevTools — and you need the actual image file back.

This tool reverses that encoding entirely in your browser.

What Is Data URI to PNG Converter?

A base64 decoder tailored to PNG data URIs: it tolerates an optional data:image/...;base64, prefix, decodes the remaining text, and validates the result really is a PNG before letting you download it.

It rejects malformed base64 and non-PNG payloads with specific error messages rather than producing a silently broken file.

How Data URI to PNG Converter Works

Any data: URI scheme prefix up through the comma is stripped via a regular expression, and the remaining text is checked against the base64 character set.

The cleaned text is decoded to raw bytes (via atob in the browser, with a Buffer fallback for tests), then the first 8 bytes are compared against the standard PNG file signature before the bytes are handed off for download.

When To Use Data URI to PNG Converter

Use it whenever you have an inline image reference — in CSS, HTML, or a JSON API response — and need to extract it as a standalone file for editing or archiving.

It's also useful for quickly sanity-checking that a data URI you're about to embed somewhere actually decodes to a valid PNG.

Features

Advantages

  • Runs entirely client-side; pasted data never leaves your browser.
  • Accepts both a full data URI and bare base64 text, so you don't need to manually strip the prefix first.
  • Validates the PNG signature before offering a download, catching corrupted or non-image input immediately.

Limitations

  • Only PNG payloads are accepted; a data URI for a different image format (JPEG, WebP, etc.) will correctly fail the PNG signature check.
  • Whitespace inside the base64 text is tolerated, but any other invalid characters cause the whole input to be rejected rather than partially decoded.

Examples

Full data URI

Input

data:image/png;base64,iVBORw0KGgo...

Output

logo.png, ready to download

The scheme prefix is detected and stripped automatically before decoding.

Bare base64 text

Input

iVBORw0KGgo... (no prefix)

Output

logo.png, ready to download

The decoder works identically whether or not the data: prefix is present.

Best Practices & Notes

Best Practices

  • Copy the entire base64 string without line breaks in the middle when pulling it from source code, since accidental truncation produces a signature-check failure.
  • Use this alongside the PNG-to-data-URI converter to round-trip and verify an embedded image matches its source file.

Developer Notes

Reuses base64-to-png-converter's pure decode-and-validate function unchanged — that function already accepts an optional data URI prefix — exposed here under the name people search for when they specifically have a full data: URI in hand.

Data URI to PNG Converter Use Cases

  • Extracting an inline background-image from a copied CSS rule
  • Recovering a standalone file from a base64 image field in an API response
  • Verifying that a data URI you're about to publish actually decodes to a valid PNG

Common Mistakes

  • Pasting a truncated data URI (common when copying from a UI that visually clips long text), which fails the PNG signature check.
  • Assuming any base64 string will work — only PNG-signature bytes are accepted, not other image formats encoded the same way.

Tips

  • If decoding fails, verify the source wasn't itself a JPEG or WebP data URI mislabeled as PNG.
  • Use your browser's 'copy full value' option in DevTools rather than the truncated preview when copying a data URI.

References

Frequently Asked Questions