Base64 to Image
Decode Base64 strings back to downloadable image files.
What it's for
From text to image in seconds
100% private
Decoding happens entirely in your browser. No data leaves your device.
Auto-detection
Automatically detects the image format (JPG, PNG, WebP...) from the prefix or magic bytes.
Instant preview
Preview the image before downloading to confirm the string is valid and correct.
Instant
Decoding in milliseconds with no data uploads or server responses to wait for.
How it works
Three steps, no hassle
Paste the Base64 string
Enter the Base64 string or complete data URI you want to decode. It can include or omit the data:[type];base64, prefix.
Automatic preview
The tool detects the image format and shows a real-time preview.
Download the image
Download the image file in the original format (JPG, PNG, WebP, or other) with one click.
FAQ
Got questions?
The process uses the browser's native atob() function to decode the Base64 string into binary data, which is then converted into a Blob object with the correct MIME type. Finally, an Object URL pointing to the Blob is created and used as the download source.
The tool can decode any image format the browser can render: JPG, PNG, WebP, GIF, SVG, AVIF, and others. The MIME type is extracted from the data URI prefix or detected from the magic bytes at the start of the decoded data.
If the string has a data URI prefix (data:image/png;base64,...), the MIME type is explicit. Without a prefix, you can identify the format from the initial bytes of the decoded binary: JPG starts with FFD8FF, PNG with 89504E47, GIF with 47494638, WebP with 52494646.
Common sources include: API responses that return encoded images, HTML emails with embedded images, CSS code with data URI background-images, HTML canvas exports, and JSON documents that transport images as text fields.
Common errors include: spaces or line breaks in the string (remove them), incomplete or malformed data URI prefix, non-Base64 characters introduced during copying (verify only A-Z, a-z, 0-9, +, /, and = are present), or a truncated string. Make sure to copy the complete string without omitting the trailing padding (=).
Base64 decoding: the technical process and its practical applications
Base64 decoding is the inverse operation of encoding: it transforms a string of ASCII characters back into the original binary data. In modern browsers, the native atob() API performs this operation, while the Blob API allows creating downloadable files from the resulting bytes. The Object URL created via URL.createObjectURL() points to the in-memory Blob and enables downloading without any server intermediary.
In modern application development, encountering images in Base64 is very common: facial recognition APIs, document scanning APIs, digital signature capture systems, and many cloud services return Base64-encoded images in their JSON responses. Being able to quickly decode and visualize these images is essential for debugging integrations and validating data.
The Object URL lifecycle matters for performance: URL.createObjectURL() allocates browser memory that isn't automatically freed until the page closes or URL.revokeObjectURL() is called. Convertir.ai manages this lifecycle correctly, freeing memory after download to prevent memory leaks in long sessions.