# JPG to PNG. Drop in a JPEG, get back a lossless PNG — instantly, free, and entirely inside your browser. Nothing leaves your device. ## Convert JPG files to PNG Drop one image or a whole batch. Each file is decoded in a canvas element inside your browser and re-exported as a lossless PNG — no quality setting to tune, no watermark, no size limit beyond your device's RAM. Drop JPG files here, or *click to browse* Accepts .jpg & .jpeg — any size, any quantity Files are processed locally · never uploaded ### JPEG — Joint Photographic Experts Group JPEG stands for **Joint Photographic Experts Group**, the ISO/IEC working group that created the standard.[[1]](#ref-1) The group published the format in 1992; it was formally approved as **ISO/IEC 10918-1** in 1994 and simultaneously as ITU-T Recommendation T.81.[[2]](#ref-2) JPEG's defining property is **lossy compression**. It works by dividing an image into 8×8 pixel blocks and applying the Discrete Cosine Transform (DCT), then discarding frequencies the human eye is least sensitive to.[[2]](#ref-2) The result is dramatically smaller file sizes than uncompressed images, at the cost of some irreversibly lost data — which is why re-saving a JPEG repeatedly degrades it. JPEG is the dominant format for photographs on the web today,[[3]](#ref-3) because photos contain complex colour gradients that compress extremely well with DCT. It supports up to 24-bit true colour (16.7 million colours), but has **no alpha channel** — transparency is not possible. - Lossy compression — some data is permanently lost on save - Excellent for photographs and complex gradients - No transparency support - File extensions: `.jpg`, `.jpeg` ### PNG — Portable Network Graphics PNG (pronounced "ping") stands for **Portable Network Graphics**. It was originally designed as a patent-free replacement for GIF, and the W3C issued the first PNG specification as a Recommendation on 1 October 1996.[[4]](#ref-4) The format is now standardised as **ISO/IEC 15948** and maintained by the W3C PNG Working Group, which published a Third Edition in 2025.[[5]](#ref-5) PNG uses **lossless compression**: every pixel is stored exactly — no data is ever thrown away, regardless of how many times you save the file. Compression is achieved through a combination of filtering (predicting pixel values from neighbours) and the DEFLATE algorithm.[[6]](#ref-6) Uniquely among widely-supported web formats, PNG supports a **full alpha channel** — per-pixel transparency from fully opaque to fully transparent. This makes it the format of choice for logos, icons, UI screenshots, and any image that must be composited onto an arbitrary background. - Lossless compression — no data loss, ever - Full alpha channel (per-pixel transparency) - Best for screenshots, logos, diagrams, UI elements - File extension: `.png` ### When to use which **Use JPEG** for photographs destined for the web when file size matters more than pixel-perfect fidelity — a hero image, a product photo, or a social-media thumbnail. The compression artefacts are typically invisible at a quality setting of 80–90. **Use PNG** when you need transparency, when the image contains text or sharp-edged graphics (where JPEG's block artefacts become visible), or when you intend to edit and re-save the file multiple times. Each JPEG re-save re-applies lossy compression; a PNG save is lossless, so editing loops don't accumulate artefacts. **Converting JPG → PNG** does *not* recover lost detail — the conversion captures the decoded pixels of the JPEG exactly as they are. The converted PNG will be pixel-identical to what you see in the JPEG viewer, just stored losslessly going forward. This is useful as an intermediate step before editing, or when a workflow requires PNG input. Sources & further reading 1. Joint Photographic Experts Group. *About JPEG.* [jpeg.org/jpeg](https://jpeg.org/jpeg/) — The committee's own description of the standard's history. 2. ISO/IEC JTC 1/SC 29/WG 1. *ISO/IEC 10918-1: Information technology — Digital compression and coding of continuous-tone still images.* 1994. Also published as ITU-T T.81 (September 1992). Cited in [ANSI Blog: The JPEG Standard](https://blog.ansi.org/ansi/jpeg-standard-iso-iec-10918/). 3. MDN Web Docs. *Image file type and format guide.* Mozilla. [developer.mozilla.org](https://developer.mozilla.org/en-US/docs/Web/Media/Guides/Formats/Image_types) — "JPEG: Good choice for lossy compression of still images (currently the most popular)." 4. World Wide Web Consortium. *PNG specification issued as W3C Recommendation* (press release, 1 October 1996). [w3.org/Graphics/PNG](https://www.w3.org/Graphics/PNG/) 5. W3C PNG Working Group. *Portable Network Graphics (PNG) Specification (Third Edition).* W3C Proposed Recommendation, 2025. [w3.org/TR/png-3](https://www.w3.org/TR/png-3/) 6. Boutell, T. et al. *PNG (Portable Network Graphics) Specification Version 1.0.* IETF RFC 2083, March 1997. [datatracker.ietf.org/doc/html/rfc2083](https://datatracker.ietf.org/doc/html/rfc2083) ## Accessibility ### Screen reader support --- *Source: [ocxly.com/jpg-to-png-converter.html](https://ocxly.com/jpg-to-png-converter.html) — OCXLY, free 100% client-side privacy-first tools. Convert JPG or JPEG photos to PNG instantly, free, and entirely in your browser — no uploads, no accounts, no watermarks. Plus: a plain-English guide to what JPG and PNG actually are.*