File format reference
What each format actually is, what it can and cannot store, and which one to choose for a given job. Written from the specifications and from our own measurements — not from marketing pages.
Image formats
- JPGJPG (also written JPEG) is a lossy image format that discards visual detail the eye is least likely to notice, which is why photographs stored as JPG are typically 5–15 times smaller than the same image stored losslessly.image/jpeg.jpg .jpeg .jpe
- PNGPNG is a lossless image format: it stores every pixel exactly as it was saved, supports a full alpha transparency channel, and never degrades no matter how many times the file is opened and saved again.image/png.png
- WebPWebP is an image format developed by Google that offers both a lossy and a lossless mode, supports transparency and animation in either mode, and is typically 25–35% smaller than a JPG of comparable quality.image/webp.webp
- AVIFAVIF stores a still image using AV1 video compression inside a HEIF container. It produces the smallest files of any widely supported image format — commonly 30–50% below a comparable JPG — and supports transparency, HDR and wide colour.image/avif.avif
- HEICHEIC is the format an iPhone saves photos in by default: HEVC-compressed images inside a HEIF container, roughly half the size of the equivalent JPG, and unreadable by most software that is not made by Apple.image/heic.heic .heif
- GIFGIF is a lossless image format limited to a 256-colour palette per frame, with frame-based animation and one-bit transparency — obsolete for still images, still universal for short looping clips.image/gif.gif
Video formats
- MP4MP4 is a container format, not a codec: it wraps video (usually H.264), audio (usually AAC) and metadata in one file, and it is the closest thing to a universally playable video file.video/mp4.mp4 .m4v
- MOVMOV is Apple’s QuickTime container — the format iPhones and Macs record into. It is structurally the ancestor of MP4 and often holds identical H.264 video, but the extension itself is enough to make many players, editors and upload forms refuse it.video/quicktime.mov .qt
- WebMWebM is an open, royalty-free video container built on Matroska, holding VP8, VP9 or AV1 video with Vorbis or Opus audio. It was designed for the web and is what most browsers produce when a page records video.video/webm.webm
Audio formats
Last reviewed 3 August 2026 · Published by FlipMyFile