{"id":"image-x-jg","mimeType":"image/x-jg","name":"AOL ART Image","shortName":"AOL-ART","category":"Legacy \u0026 Proprietary","extensions":[".art"],"description":"The image/x-jg MIME type represents the ART image format, a proprietary, highly compressed raster graphic format developed by the Johnson-Grace Company in the mid-1990s. America Online (AOL) acquired the company and integrated the format heavily into its dial-up service and custom web browsers. To save bandwidth over slow 14.4k and 56k modems, AOL proxy servers famously intercepted standard web JPEGs and GIFs and transcoded them on-the-fly into the .art format before sending them to users. While it provided exceptionally fast progressive loading, it was notorious for introducing heavy compression artifacts and is now completely obsolete.","seo":{"title":"image/x-jg MIME Type | Developer Reference for AOL ART Images","description":"Complete reference for the image/x-jg MIME type: AOL ART images, Johnson-Grace compression, dial-up internet history, and .art file detection.","faqs":[{"question":"What is an AOL ART (.art) file?","answer":"An ART file is a legacy, highly compressed image format developed by Johnson-Grace and used extensively by America Online (AOL) in the late 1990s and early 2000s to speed up web browsing over dial-up modems."},{"question":"Why did AOL convert standard JPEGs to ART files?","answer":"During the dial-up era, bandwidth was severely limited. AOL used proxy servers to intercept web traffic and compress standard JPEGs and GIFs into the smaller .art format on-the-fly. This loaded pages much faster for users, though it notoriously degraded image quality."},{"question":"How can I open or convert a legacy .art file today?","answer":"Because the format is proprietary and was never fully open-sourced, modern web browsers and standard image editors like Photoshop cannot open it. You must use specialized legacy software like XnView, GraphicConverter, or the original AOL Desktop software to view or convert them."}]},"index":{"compression":["Proprietary Wavelet (Photos)","Proprietary Palette-based (Graphics)"],"browserSupport":{"score":1,"label":"None"},"commonUses":["Historical AOL Dial-up Web Browsing","Legacy America Online Client Assets","1990s Internet Archival"]},"technical":{"magicBytes":{"hex":"4A 47 03 00 or 4A 47 04 00","ascii":"JG\\x03\\x00 or JG\\x04\\x00"},"container":"Johnson-Grace Proprietary","compressionAlgorithm":["Wavelet (similar to early JPEG 2000 concepts)","Lossy DCT"],"colorDepth":["8-bit (Indexed)","24-bit (RGB)"],"transparency":false,"animation":false,"metadata":{"exif":false,"xmp":false,"iccProfile":false},"alphaChannel":false,"progressiveLoading":true,"hdrSupport":false},"history":{"developer":"Johnson-Grace Company (Acquired by AOL)","released":"1994","specification":"Proprietary (Closed Source)"},"browserSupport":{"chrome":false,"chromeVersion":"None","firefox":false,"firefoxVersion":"None","safari":false,"safariVersion":"None","edge":false,"edgeVersion":"None","internetExplorer":false},"softwareSupport":[{"name":"XnView","logo":""},{"name":"GraphicConverter (macOS)","logo":""},{"name":"AOL Desktop (Legacy)","logo":""}],"conversion":{"convertTo":["jpeg","png","gif"],"convertFrom":[]},"developer":{"httpHeaders":[{"header":"Content-Type","value":"image/x-jg"}],"htmlAccept":"None","fileDetection":["Check the first two bytes for the 'JG' ASCII string (Hex: 4A 47), which stands for Johnson-Grace.","The following byte typically indicates the version format (e.g., 0x03 or 0x04).","Be aware that the '.art' extension is heavily overloaded and also used by older formats like PFS:Art, Ray Tracer, and Bernina embroidery files. Checking the magic bytes is critical."]},"prosCons":{"pros":["Historically provided massive file size reductions (up to 3x smaller than JPEGs of the era) and highly optimized progressive rendering for 14.4k modems","Enabled faster web browsing on the AOL network during the early days of the commercial internet"],"cons":["Completely proprietary, heavily patent-encumbered, and never officially reverse-engineered for the open-source community","On-the-fly proxy compression ruined the visual fidelity of many 1990s websites for AOL users","Virtually impossible to open on modern operating systems without installing niche, legacy image viewers"]},"specifications":{"url":"http://justsolve.archiveteam.org/wiki/ART_(AOL)","rfc":"","mimeAliases":["image/jg","image/art","image/x-art"]},"developerSnippets":{"python":"import magic\n# Libmagic can often identify the Johnson-Grace header\nprint(magic.from_file('vintage.art', mime=True)) # May output 'image/x-jg' or generic 'application/octet-stream' depending on definitions","nodejs":"const fs = require('fs');\n// Manually detecting the 'JG' magic bytes to differentiate from other .art files\nconst buffer = Buffer.alloc(2);\nconst fd = fs.openSync('vintage.art', 'r');\nfs.readSync(fd, buffer, 0, 2, 0);\nfs.closeSync(fd);\nconst isAolArt = buffer[0] === 0x4A \u0026\u0026 buffer[1] === 0x47; // 'J' and 'G'\nconsole.log('Is AOL ART (Johnson-Grace):', isAolArt);","go":"import (\n    \"bytes\"\n    \"net/http\"\n)\n// Native Go HTTP detection will not recognize the ART format.\n// You must explicitly check for the 2-byte signature.\n// isAolArt := bytes.HasPrefix(buf, []byte{0x4A, 0x47})","php":"$mime = mime_content_type('vintage.art');\necho $mime; // Standard PHP setups will likely return 'application/octet-stream'. Custom magic.mime rules are required."},"relatedFormats":["jpeg","gif"]}