Base64 Image Viewer
Paste a Base64 string or a data:image/...;base64,... URL to check it, preview the picture, and download the restored file. Everything is validated and rendered locally in your browser.
Accepted: raw Base64 or a data URL of a PNG, JPEG, GIF, WebP, BMP, ICO, or AVIF image. SVG and other document types are rejected.
| Format | |
|---|---|
| MIME type | |
| Dimensions | |
| Decoded size | |
| Source |
How to use
- Copy a Base64 string or a complete
data:image/...;base64,...URL. - Paste it above and press Preview image.
- The picture appears with its format, dimensions, and decoded size.
- Press Download image to save the restored file, with the correct file extension.
What gets validated
- The Base64 characters and padding are checked before anything is decoded; missing padding is fixed automatically.
- For data URLs, the media type must be a supported bitmap image type. SVG is rejected on purpose — SVG documents can contain scripts, so untrusted SVG is never rendered here.
- The decoded bytes are checked against known image signatures (magic numbers). A data URL whose declared type does not match the actual bytes is refused with an explanation.
- The image is only shown after your browser has actually decoded the bytes — a valid signature alone is not enough.
- Nothing in your input is ever inserted into the page as HTML; the preview is rendered from a locally generated blob.
Limits
- Decoded images up to 16 MiB.
- Formats: PNG, JPEG, GIF, WebP, BMP, ICO, and AVIF, subject to what your browser can decode. Animated GIFs play in the preview exactly as the browser renders them; frame-by-frame inspection is not included.
- No remote fetching: this tool never downloads images from URLs — pasted content only.
Frequently asked questions
What can I paste into this viewer?
A raw Base64 string of an image, or a full data URL like data:image/png;base64,iVBORw0KGgo…. With a raw string, the format is detected from the decoded bytes; with a data URL, the declared media type is also verified against the actual content.
Which image formats are supported?
PNG, JPEG, GIF (including animated), WebP, BMP, ICO, and AVIF — in practice, whatever your browser can decode, because the browser performs the final decode. If the browser cannot decode the bytes, the tool tells you instead of showing a broken image.
Why was my SVG or data:image/svg+xml input rejected?
SVG is an XML document format, not a plain bitmap, and SVG files can embed scripts. Previewing untrusted SVG would mean running potentially hostile content, so it is excluded from this first version. Convert the SVG to PNG first if you need to preview it.
What does "declared type does not match the data" mean?
The bytes of every image format start with a known signature. If a data URL says image/png but the decoded bytes start with a JPEG signature, the input is lying about its content and is rejected. This protects you from mislabeled payloads.
Is there a size limit?
Yes: the decoded image may be at most 16 MiB. Larger inputs are refused with a clear message rather than freezing the page.
Can I edit or convert the image here?
No — this tool previews, verifies, and downloads the original file. It does not edit, resize, or convert images, and it does not extract frames from animated GIFs.
Is my image uploaded anywhere?
No. Decoding, validation, and rendering happen entirely in your browser. The page loads no third-party scripts and sends nothing anywhere — you can verify this in your browser's network panel.