Do I need the data URI prefix?

No. A full data:image/png;base64,... URI works, and so does a bare Base64 payload — in that case the image type is detected from the decoded bytes.

How does it know the image type without a prefix?

It reads the first few decoded bytes (the file magic numbers): 0x89 0x50 means PNG, 0xFF 0xD8 means JPEG, 0x47 0x49 means GIF, an RIFF/WEBP header means WebP, and 0x42 0x4D means BMP.

Which image formats are supported?

PNG, JPEG, GIF, WebP, BMP, SVG and ICO are recognised. From a data URI the exact MIME type is used; from raw bytes the type is sniffed and defaults to PNG if unknown.

What if my Base64 has line breaks or spaces?

Whitespace and newlines are stripped automatically before decoding, so Base64 copied from emails, certificates or code wraps decodes cleanly.

Why is my decoded image broken or blank?

Usually the Base64 is truncated or contains characters from outside the image data. Make sure you copied the entire payload, including any data: prefix, with nothing cut off.

Is my image uploaded anywhere?

No. Decoding uses the browser's built-in atob and Blob APIs entirely on your device — the data is never sent to a server or stored.

Base64 to Image — Gera Tools

Decode Base64 back into an image

Paste a Base64 string — either a bare payload or a full data: URI — and get the image back, ready to view and download. This is the reverse of embedding an image as Base64 in CSS, HTML or JSON, and it is handy for inspecting data URIs pulled from a stylesheet, API response or saved page.

How it works

If the input starts with a data:image/...;base64, prefix, the tool reads the exact MIME type from it. For a bare payload it decodes the bytes and sniffs the type from the file’s magic numbers — for example a PNG starts with 89 50, a JPEG with FF D8, and a BMP with 42 4D. The decoded bytes are wrapped in a Blob of the right type, rendered as a preview, and offered for download with the matching extension.

Example

Pasting data:image/png;base64,iVBORw0KGgo... shows the PNG preview and offers a .png download. Pasting the same payload without the prefix still works — the leading bytes 89 50 4E 47 identify it as PNG automatically.

Detected bytes	Image type	Extension
`89 50`	PNG	.png
`FF D8`	JPEG	.jpg
`47 49`	GIF	.gif
`42 4D`	BMP	.bmp

Everything happens in your browser with the built-in atob and Blob APIs — nothing is uploaded.