Base64 to image, previewed and ready to download.

Images embedded in HTML, CSS, JSON and email usually arrive as a data URI: data:image/png;base64,iVBORw0KGgo…. Everything before the comma is a label; the image is the Base64 after it. Paste either form here. When a prefix is present it is stripped, but the decoder still checks the file signature itself, so an image mislabelled as image/png that is really a JPEG is still identified and saved correctly.

To embed the decoded image somewhere else, you do not need to decode it at all: a data URI can be used directly as an <img src> or a CSS url(). Decoding is for when you need the file itself — to edit it, inspect it, or check what an API actually returned.

Because Base64 maps the same bytes to the same characters, every file format has a recognisable opening. You can tell what a Base64 string contains before decoding it:

A string that starts with /9j/ is a JPEG, iVBORw0KGgo is a PNG — useful when a log line or a database column gives you nothing else to go on.

• The string is truncated. Long Base64 values are often cut off by log viewers, chat apps and spreadsheet cells (Excel stops at 32,767 characters). The header decodes but the image data is incomplete. Copy the value from the original source.
• It is not an image. Check the Type field under the output. If it says PDF, ZIP or Binary data, the Base64 holds a different kind of file — download it instead.
• The format is not displayable. Browsers cannot render HEIC or TIFF, so those files decode correctly but cannot be previewed. Download them and open them in an image viewer.
• It was encoded twice. If the output is more Base64 (often starting with aVZCT1J3, which is “iVBORw” encoded again), press Send to input and decode a second time.

# Python
import base64
with open("image.png", "wb") as f:
    f.write(base64.b64decode(b64_string))

// Node.js
fs.writeFileSync("image.png", Buffer.from(b64String, "base64"));

# Linux / macOS shell
base64 --decode image.b64 > image.png

Strip any data:image/…;base64, prefix before decoding in code — most decoders treat the prefix as invalid input. More languages are covered in the Base64 decode code snippets.