JPEG remains the universal photo format — supported by every device, printer, photo lab, social platform, and legacy CMS on Earth. This converter takes any modern format (HEIC from an iPhone, AVIF from a next-gen source, PNG, WebP, and legacy raster formats) and produces JPEGs using MozJPEG, the encoder Mozilla built to be a drop-in replacement for libjpeg-turbo that produces measurably smaller files at the same visual quality. On top of MozJPEG's baseline savings, this tool enables trellis quantization with 6 loops, separate chroma quality, and progressive encoding — settings that most online converters skip. Result: JPEG files 8–15% smaller than what you get from Photoshop's "Save for Web" or your OS's built-in export.
When to convert to JPEG in 2026
Convert to JPEG when you need universal compatibility: emailing photos to non-technical recipients, uploading to a legacy CMS or old CRM, sending to a print lab, posting to a platform that strips modern formats, or generating fallback images for a <picture> element. For the web, prefer WebP or AVIF as your primary format and use JPEG only as a fallback for browsers older than 2020 — but for everything else, JPEG is still the default that just works everywhere.
Why MozJPEG?
MozJPEG is a fork of libjpeg-turbo maintained by Mozilla with better encoding heuristics: smarter quantization tables, trellis optimization, and progressive scan by default. At quality 82, a MozJPEG-encoded photo is typically 8–15% smaller than the same photo encoded by libjpeg-turbo or Photoshop's default JPEG exporter — with no visible quality difference. This tool uses MozJPEG compiled to WebAssembly, runs entirely in your browser, and layers on trellis multipass with 6 loops for another few percent of savings.
Handling transparency (PNG → JPEG)
JPEG does not support transparency — every pixel is opaque RGB. When you convert a PNG with an alpha channel, the tool flattens transparent regions onto white by default. If your PNG is a logo on transparent background meant to sit on a dark theme, you'll get a white halo. In that case, either keep it as PNG/WebP (both support alpha) or resize the PNG onto the correct background color first. Fully-opaque PNGs convert to JPEG cleanly with no visible difference.
HEIC to JPEG for compatibility
iPhone photos default to HEIC, which most Windows apps, older email clients, and printing services still can't open in 2026. This tool decodes HEIC in your browser using libheif WASM (no Apple software needed) and re-encodes as JPEG. Because HEIC and JPEG use similar-quality lossy compression, converting doesn't add significant loss — the output JPEG is usually within 5% of the source file size while being playable everywhere. Bulk-drop 20 iPhone photos and get a zip of JPEGs in seconds.