It says my base64 is invalid. What went wrong?

Valid base64 only contains A–Z, a–z, 0–9, + and / with optional = padding at the end. Common causes: missing characters from an incomplete copy-paste, or extra text accidentally included.

How does the tool know the image format?

It first checks the data URL's mime type if present, then falls back to reading the file's magic bytes, so JPEG, PNG, GIF, WebP, SVG and BMP are all detected even from raw base64.

Is my base64 string sent anywhere?

No. Decoding happens entirely in your browser; the string never leaves your device.

Base64 to Image

Decode a base64 string back into a downloadable image.

Paste your base64 string

A full data:image/…;base64,… URL works, and so does the raw base64 without the prefix.

Everything happens in your browser, your base64 string is never sent anywhere.

About this tool

JoliTools Base64 to Image turns a base64-encoded string back into a real image file. Paste the string, a full data URL from an <img> tag or the raw base64 alone, and the tool validates it, decodes it, detects the image format from its magic bytes, and shows you a preview with the file size.

This is the reverse of embedding: developers often need to extract an image that was inlined as base64 in code, an email, or a JSON API response. The decoder handles whitespace and line breaks, so you can paste strings copied from pretty-printed source files without cleaning them up first.

How to use the base64 to image

1Paste your base64 string, with or without the data:image/...;base64, prefix.
2Click Decode to image.
3Preview the image and check the detected format and file size.
4Click Download image to save it with the correct file extension.
5Use Clear to start over with a new string.

Good to know

Once decoded, the image downloads with the correct extension (JPG, PNG, GIF, WebP, SVG or BMP) so it opens properly everywhere. Everything runs locally in your browser, and invalid input gets a clear explanation of what looks wrong instead of a cryptic error.