Data URI to JPEG Converter

Data URIs, defined by RFC 2397, allow developers to embed small files directly inline within HTML or CSS using Base64 encoding. While highly efficient for minimizing HTTP requests, these long strings of characters are unusable when a physical image file is required for saving, sharing, or standard content management systems. Furthermore, Base64 encoding incurs a mathematical overhead, expanding the file's footprint by exactly 13 compared to its binary equivalent.

This tool performs a secure, client-side extraction of the binary payload. It isolates the MIME type, decodes the Base64 matrix, and utilizes the browser's native rendering engine to transcode the visual data into a standard Joint Photographic Experts Group (JPEG) format. Crucially, because the JPEG standard does not support an alpha channel (transparency), the conversion algorithm automatically applies a solid #FFFFFF background raster beneath the image data to prevent black-matte artifacts common when extracting transparent PNG or WebP Data URIs.

The mathematical relationship between a Base64 encoded string and its actual binary file size is strictly proportional due to the 6-bit encoding scheme (where 4 Base64 characters represent 3 bytes of binary data). The estimation formula is:

Where L represents the total character length of the Base64 string (excluding the data:image/...;base64, header), and P represents the number of padding characters (=) at the end of the string, which can be 0, 1, or 2.