Base64 to image

If you have a Base64 string or a data URI and need the actual image, decoding it is the reverse of inlining: the text becomes bytes again, which you can preview and save as a normal file. This guide covers what the decoder accepts, how it works out the format, and the common reasons a string fails to decode.

What you can paste

The decoder takes either a full data URI, the kind that starts with data:image/png;base64, or a bare Base64 blob with no prefix. Both are common: code and dev tools often hand you the whole data URI, while a config value or a database field might hold only the raw string.

Ordinary whitespace and line breaks are ignored, so a string that was wrapped across lines when it was copied still works. What cannot be fixed is a string that was cut short, since the missing bytes are simply gone.

As soon as a valid string is in the box, the image renders, so you get immediate confirmation that you pasted the right thing.

How the format is detected

When you paste a full data URI, the MIME type in the prefix says what the image is. But the decoder does not rely on that alone: it also inspects the first few decoded bytes, the file's signature, to confirm the real format.

That signature check is why a bare Base64 string still works without a prefix. A PNG always begins with the same magic bytes, a JPEG with its own, and so on, so the format can be named from the content rather than a label.

Knowing the true format means the download gets the correct extension, so the saved file opens cleanly in any viewer.

When decoding fails

The usual culprit is an incomplete string. If only part of the Base64 was copied, it cannot rebuild the image, and the tool says so rather than saving a broken file. The fix is to copy the entire value again.