UTIF.js is a comprehensive, single-file JavaScript library for decoding and encoding TIFF, EXIF, DNG, CR2, NEF, and other TIFF-based image formats. It is the primary TIFF library used by the Photopea online image editor. The library handles a wide variety of compression schemes (JPEG, LZW, PackBits, Fax, Deflate, Nikon, Panasonic, etc.) and supports various bit depths, color spaces, and photometric interpretations. It provides a straightforward API: `UTIF.decode()` for parsing TIFF headers, `UTIF.decodeImage()` for decompressing pixel data, and `UTIF.toRGBA8()` for converting to RGBA. The code is monolithic, embedding its own JPEG decoder and many other decoders directly in a single file. While functional and battle-tested, the code is dense, uses ES5 patterns, and contains many minified-like variable names, making it less readable and maintainable. The library depends on the outdated `pako` v1.x for deflate compression. It is a mature, production-ready library but with medium technical drift and a maintenance status that appears active (last commit dated 2026-05-04, though this date is likely a mistake).