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Base64 to Image Decoder
Quick answer
Paste a Base64 string or a full data URI and get back a real image file you can preview and download, whether or not the text includes the data: prefix.
What the base64 to image decoder does
Paste in either a bare Base64 string or a complete data URI beginning with data:image, and the tool decodes it back into an actual image, shown as a preview with a download button beneath it. It accepts both forms because Base64 image strings show up copied from different places: sometimes with the full data: prefix and MIME type intact, sometimes as just the raw encoded characters with everything else stripped off by whatever it was copied from.
Rather than trusting a declared or assumed MIME type, the tool inspects the first few decoded bytes of the actual data for a magic number, the short signature every image format writes at the start of the file, such as the specific byte sequence that opens every valid PNG or the marker that opens a JPEG. That means the detected format reflects what the bytes actually are, not what a data URI prefix claimed them to be, which matters if the string was edited, truncated, or copied without its original header.
This is the natural companion to the encoding side: something produces a Base64 string, whether that is an API response, a database field, or a config file, and at some point a human needs to actually look at what image that string represents rather than staring at a wall of text.
How to use it
Paste the string
Paste a Base64 string with or without the data:image prefix into the input box.
Let it decode
The tool reads the decoded bytes and identifies the real image format from its magic number.
Check the preview
Confirm the rendered image is what you expected before saving it.
Download the file
Save the decoded image to your device in its detected format.
Your images never leave your device
A support engineer debugging a bug report that includes an inline Base64 screenshot from a log file, or a developer inspecting what image is actually stored in a database column, both need to view the decoded result without pasting potentially sensitive log data into a random online decoder. The decoding happens entirely in your browser, so the string never leaves your machine on its way to becoming a viewable image.
- No file is ever uploaded to a server
- Works offline after the first visit
- No account, no watermark, no limits
Format and quality tips
A failed decode usually means truncated input
If the preview does not render, the most common cause is that the copied string got cut short, often by a text field with a length limit or a copy operation that missed the last few characters. Re-copy the full string from its source rather than assuming the tool itself failed.
Do not trust a file extension over the detected format
If you saved a string as an .txt file before pasting it here, or the source mislabeled the MIME type, the format shown after decoding, based on the actual magic number in the bytes, is the reliable answer, not whatever extension or label the string arrived with.
Frequently asked questions
Do I need to include the data:image prefix when pasting?
No, the tool accepts a bare Base64 string just as well as a full data URI with the prefix and MIME type included.
How does the tool know what image format the string is?
It reads the magic number, a short signature at the start of the decoded bytes, rather than trusting whatever MIME type the data URI prefix claims, so the detected format matches the actual file content.
What happens if the Base64 string is incomplete?
Decoding will typically fail or produce a corrupted preview; this almost always means the string was truncated when it was copied, not that the tool encountered an unsupported format.
Can I decode a string copied from a JSON file or a database?
Yes, as long as you paste just the Base64 value itself, with or without a data URI wrapper, the surrounding JSON keys or quotes should be removed first.
Is the decoded image identical to the original file?
Yes, Base64 decoding reverses the encoding exactly with no loss, so the resulting file is byte-for-byte the same as whatever was encoded in the first place.
What image formats can this tool detect?
Common raster formats including PNG, JPEG, GIF and WebP are recognized by their distinct magic numbers in the decoded byte stream.
Further reading
- How to Watermark Photos: A Practical GuideA watermark buys you attribution and friction, not protection. Here is how to place, size and batch one so it actually reads — and an honest look at what metadata credit can and cannot do.6 min read
- How to Blur Faces and Redact Photos ProperlyA blur only protects you if the hidden pixels are gone from the exported file — and if the blur is strong enough that nobody can rebuild what was under it. Here is how to get both right.7 min read
- Favicon Sizes and Formats: A Complete GuideYou need fewer favicon sizes than most generators produce, but the ones you need are specific. Here is what each size is for, the exact HTML and manifest, and why a full logo turns to mush.6 min read