Images embedded as Base64 strings in web applications follow the data URI format specified by RFC 2397: data:[mediatype];base64,[data]. The media type identifies the image format — image/png, image/jpeg, image/gif, image/webp, or image/svg+xml. The browser's native image rendering engine decodes the Base64 data and displays the image exactly as it would from a standard file URL — but with no additional HTTP request and no dependency on an external server.
Each image format has a unique binary signature called magic bytes at the beginning of its raw data. After Base64 decoding, these bytes identify the format even when no data URI prefix is present. PNG images begin with the bytes 89 50 4E 47, which Base64-encodes to iVBOR. JPEG images begin with FF D8 FF, Base64: /9j/. GIF images begin with 47 49 46 38, Base64: R0lGO. WebP images begin with 52 49 46 46, Base64: UklG. This is how the tool detects image format from raw Base64 strings before rendering them.
Base64 images appear most commonly in API responses that bundle image data alongside other JSON fields, in HTML email templates where external image URLs are blocked, in CSS for small embedded icons and gradients, and in SVG files that embed raster images internally. They are also used in Content Security Policy (CSP) environments that restrict loading from external URLs.
A developer is integrating a third-party identity verification API. The API response includes a user's uploaded ID document as a Base64-encoded JPEG inside a JSON field. Before writing any image display code, she pastes the Base64 string into this tool to visually confirm the API is returning valid image data. The tool instantly renders the JPEG preview — saving the time it would take to write a temporary display component, create a test page, or build decoding logic just to see whether the API response is correct.
In another case, a developer is debugging an HTML email template. An image displays correctly in the browser preview but shows as a broken icon in Outlook. He extracts the Base64 string from the img src attribute and pastes it here. The tool confirms the Base64 is valid and renders correctly — but a closer look at the data URI reveals it is using image/jpg as the MIME type instead of the correct image/jpeg. Some email clients reject the incorrect MIME type. The fix is a one-character change in the data URI prefix.
Data URI size limits vary by browser and context. Modern browsers support data URIs up to several megabytes in HTML attributes. CSS data URIs over ~32 KB can cause noticeable rendering slowdowns on some browsers. For images larger than 100 KB, a separate file URL with proper caching is almost always more efficient than a data URI — the browser must parse and decode the entire Base64 string on every page load rather than serving a cached file.
Strip the data URI prefix when working with APIs. Many APIs and server-side libraries expect raw Base64 without the data:image/png;base64, prefix. If you receive a data URI and need to pass only the Base64 portion to an API, copy everything after the comma. This is a frequent source of confusion and 400 Bad Request errors when integrating image upload APIs.
SVG images can be embedded as Base64 data URIs, but this is rarely the best approach. SVG is text-based XML, so it can also be inlined directly in HTML without any encoding: <img src="data:image/svg+xml,<svg>...</svg>"> (with URL encoding) or placed directly as an inline <svg> element in the HTML. Inline SVG without Base64 is smaller, indexable, and styleable with CSS — prefer it over Base64-encoded SVG when the context allows.
This decode base64 image tool converts Base64 strings directly in your browser. Paste any Base64 image string — raw or as a data URL — and get an instant preview. The image never leaves your device. Useful for debugging API responses, email attachments, and embedded assets.
Paste your Base64 string into the input field above. This base64 to image converter automatically detects the image format from the data and renders a live preview. You can then download the image or copy the data URL. Both raw Base64 strings and full data URLs (data:image/png;base64,...) are accepted.
This base64 to image tool supports PNG, JPEG, GIF, WebP, SVG, and BMP. The format is detected automatically from the Base64 data — either from the data URL prefix (data:image/png;base64,...) or from the image magic bytes in the raw data.
Use the full data URL format: data:image/png;base64,YOURBASE64STRING. In HTML: <img src="data:image/png;base64,...">. In CSS: background-image: url("data:image/png;base64,..."). The data URL embeds the image directly in the code — no separate file needed.
Common causes: the Base64 string is not image data (it may be encoded text), the string is truncated or missing padding, or it contains whitespace that should be removed. Make sure you're pasting the entire Base64 string without line breaks. This tool shows an error message if the data cannot be decoded as an image.
No. This decode base64 image tool runs entirely in your browser. Your Base64 data is never transmitted anywhere. The image rendering happens locally using the browser's native image rendering engine. You can verify this by checking the Network tab in DevTools — there are zero outbound requests.