Base64 to Image Decoder

Paste your Base64 encoded string and instantly preview and download the image. Supports PNG, JPEG, GIF, WebP, SVG. 100% client-side — your data never leaves your browser.

100% Client-Side No Upload Needed Instant Preview All Formats
Your data stays private. Everything is processed locally in your browser — nothing is uploaded to any server.

How to Decode Base64 to Image

1

Paste

Paste your Base64 string into the text area above. Accepts raw Base64 or a full data URI with MIME type prefix.

2

Preview

Click Decode Image to instantly preview the decoded image. Format, dimensions, and file size are auto-detected.

3

Download

Click Download Image to save the file to your device. The correct file extension is applied automatically.

What is Base64 Image Encoding?

Base64 is a binary-to-text encoding scheme that converts binary data into a sequence of printable ASCII characters. It uses 64 characters — the letters A–Z, a–z, the digits 0–9, and two additional symbols (+ and /) — to represent arbitrary binary data as plain text. The name "Base64" comes from this 64-character alphabet.

When an image is Base64-encoded, every 3 bytes of the original binary file are represented as 4 ASCII characters. This means Base64-encoded data is approximately 33% larger than the original binary, but the trade-off is that the data can be safely embedded in text-based formats like HTML, CSS, JSON, XML, and email messages.

A Base64-encoded image is often wrapped in a data URI format: data:image/png;base64,iVBORw0KGgo.... The prefix specifies the MIME type (image/png, image/jpeg, etc.) and the encoding (base64), followed by the actual encoded data. This data URI can be used directly in an HTML <img> tag's src attribute or in CSS background-image properties, allowing the image to be embedded inline without a separate HTTP request.

Common Use Cases

Email attachments (MIME)

Email protocols (SMTP) are text-based and cannot transmit raw binary data. Base64 encoding is the standard method for embedding images and attachments in email messages via MIME (Multipurpose Internet Mail Extensions). When you need to extract an image from a raw email source, you will encounter Base64-encoded data that this tool can decode.

CSS background images

Small images like icons, logos, and UI elements can be embedded directly in CSS as Base64 data URIs. This eliminates additional HTTP requests and is commonly used in performance-optimized stylesheets. Decoding these strings lets you extract and edit the original image files.

Single-file HTML documents

Self-contained HTML files — used for reports, documentation, and dashboards — embed all assets as Base64 to work without external dependencies. If you receive such a document and need to extract an image, paste its Base64 string here to get the original file.

API responses & JSON payloads

Many APIs return images as Base64-encoded strings within JSON responses. This is common in document processing APIs, OCR services, screenshot APIs, and image generation tools. Decoding the response lets you preview and save the image without writing code.

Supported Image Formats

This decoder auto-detects the image format from the Base64 data header or the data URI MIME type. The following formats are supported:

Format Extension Detection Method Notes
PNG .png Header: iVBOR Lossless compression, transparency support
JPEG .jpg Header: /9j/ Lossy compression, photos
GIF .gif Header: R0lGOD Animation support, 256 colors
WebP .webp Header: UklGR Modern format, lossy & lossless
SVG .svg Header: PHN2Zy / PD94bW Vector graphics, XML-based
BMP .bmp Header: Qk0 Uncompressed bitmap
ICO .ico Header: AAABAA Favicon / icon format

Frequently Asked Questions

Yes. This tool is 100% client-side — your Base64 data is processed entirely in your browser using JavaScript. Nothing is uploaded to any server. Your data never leaves your device, making it safe for sensitive or private images.
The decoder supports all common image formats: PNG, JPEG, GIF (including animated GIFs), WebP, SVG, BMP, and ICO. The format is auto-detected from the Base64 data or from the data URI prefix if present.
The tool handles both formats automatically. You can paste a raw Base64 string (e.g., iVBORw0KGgo...) or a full data URI (e.g., data:image/png;base64,iVBORw0KGgo...). The prefix is stripped automatically and the MIME type is used for format detection.
There is no hard server-side limit since everything runs in your browser. However, very large Base64 strings (over 50 MB of decoded data) may cause your browser to slow down or run out of memory. For typical images (up to 10–20 MB), the decoder works instantly.
Yes. If the Base64 string encodes an animated GIF, the decoded image will retain all animation frames. The preview will show the animation playing, and the downloaded file will be a fully animated GIF.
Base64 is a binary-to-text encoding scheme that represents binary data (like images) as ASCII text using 64 characters (A–Z, a–z, 0–9, +, /). It is commonly used to embed images directly in HTML, CSS, JSON, emails (MIME), and API responses. Base64 increases the data size by approximately 33% compared to the original binary, but allows binary data to be safely transmitted through text-only channels.

Related Conversions

Image to Base64 JPG to PNG PNG to JPG HEIC to JPG