Reading an Image From Base64 Magic Bytes
The first few bytes of a file are its signature. This guide shows how PNG, JPEG, GIF, and WebP signatures identify a decoded base64 image.
What is the Base64 to Image Converter?
Base64 strings hide images inside text, which makes them hard to check at a glance. This tool decodes the string, reports its byte length, and reads the first bytes to name the format, such as PNG or JPEG. In a browser it also shows the image itself and offers a download link.
How to use it
- Paste a base64 image string, with or without its data URL prefix.
- Click Convert Base64 to Image.
- Read the byte length and detected format.
- In a browser, preview the image and use the download link.
Worked example
For the sample one-pixel PNG string, the tool reports a PNG format with a positive byte length.
How can you tell an image format from base64?
Decode it and inspect the opening bytes: PNG starts with a distinctive eight-byte signature, JPEG with FFD8, GIF with its letters, and WebP with RIFF and WEBP markers.
Frequently asked questions
What if the format says unknown?
The bytes do not match a known image header, so the string may be truncated, encoded text, or another file type.
Does it accept a full data URL?
Yes. A leading data URL prefix is stripped before decoding.