概述
本指南在最重要的标准上比较WebP和JPG，以帮助您选择适合您需求的正确格式。
WebP在相同质量下提供比JPG小25-35%的文件，但JPG具有更好的通用支持。
Head-to-Head Comparison
Compression
WebP: WebP在相同质量下比JPG小25-35%。
JPG: JPG经过数十年的优化，但效率不如WebP。
Winner: WebP
浏览器支持
WebP: WebP受到所有现代浏览器的支持（Chrome、Firefox、Edge、Safari 14+）。
JPG: JPG几乎被每个设备和应用程序支持。
Winner: JPG
透明度
WebP: WebP支持alpha通道透明度。
JPG: JPG不支持透明度。
Winner: WebP
软件支持
WebP: WebP 在图像编辑器（Photoshop, Lightroom）中获得了越来越多的支持。
JPG: JPG 被所有曾经制作的图像工具支持。
Winner: JPG
使用案例
WebP: WebP 非常适合网页优化和减少页面加载时间。
JPG: 当需要与旧软件兼容时，JPG 更好。
Winner: 平局
Technical Foundations
JPG compresses 8x8 pixel blocks with a discrete cosine transform and quantization, a design from the early 1990s optimized for photographs.[3] WebP, defined by Google and standardized in RFC 9649, reuses intra-frame prediction techniques from the VP8 video codec: it predicts blocks from already-decoded neighbors before transform coding, and supports both lossy and lossless modes within a RIFF container.[1][2] This predictive step removes more redundancy than JPG's block-isolated approach.
Compression and File Size
For comparable visual quality, WebP lossy images are generally smaller than baseline JPG, with reductions commonly reported in the range of 25 to 35 percent depending on content and quality settings.[1] The advantage is largest at low-to-moderate quality and narrows at very high quality. WebP also offers a lossless mode that competes with PNG rather than JPG, giving the single format a wider operating range than JPG, which is lossy only.
Color, Transparency, and Animation
JPG encodes in YCbCr with chroma subsampling and has no alpha channel, so it cannot store transparency.[4] WebP natively supports an alpha channel for variable transparency in both its lossy and lossless modes, and can store animation as a sequence of frames.[1][2] JPG supports neither transparency nor animation. WebP's bit depth is limited to 8 bits per channel, the same as JPG.
Standardization and History
JPEG was standardized as ITU-T T.81 and ISO/IEC 10918-1, with files commonly using the JFIF convention.[3][4] WebP was introduced by Google in 2010 and later formalized as RFC 9649 by the IETF.[1] WebP is preserved in the Library of Congress sustainability registry as a documented web image format.[2]
Compatibility and Applications
JPG's long history gives it universal support across cameras, browsers, operating systems, and image tools, making it the safest interchange format for photographs.[3] WebP is supported by all current major browsers and is used widely for web delivery, where smaller payloads and transparency reduce page weight; some older or specialized software cannot read it.[1] A common practice is to serve WebP with a JPG fallback for clients that lack WebP support.