概述
PNG 是需要透明度的图形的传统格式。WebP 是具有更好压缩的现代替代方案。SVG 是一种矢量格式，可以无限缩放而不会损失质量。
对于徽标和图标，SVG 几乎总是正确的选择。对于复杂的光栅图形，PNG 和 WebP 更好。
正面比较
可扩展性
PNG: PNG 是光栅 - 放大时会导致像素化。您需要为每个分辨率提供单独的文件。
WebP: WebP 也是光栅 - 与 PNG 相同的缩放限制。
Winner: SVG（无限缩放，无质量损失）
文件大小
PNG: PNG 是无损的，文件较大。一个复杂的徽标可能为 50-200KB。
WebP: WebP-无损比 PNG 小 25-35%。相同的徽标可能为 35-150KB。
Winner: SVG（通常仅为 1-20KB）
透明度
PNG: PNG 完全支持 alpha 通道透明度。
WebP: WebP 完全支持 alpha 通道透明度，并且压缩效果优于 PNG。
Winner: SVG / WebP
动画
PNG: PNG 支持带有完全透明度的动画 APNG 格式。
WebP: WebP 支持动画，文件大小比动画 GIF 或 APNG 更小。
Winner: SVG（CSS/JS 动画）
浏览器支持
PNG: PNG 在 100% 的浏览器和设备中得到支持。
WebP: WebP 在 97% 以上的浏览器中得到支持。
Winner: PNG
Two Raster Formats and a Vector Format
PNG and WebP are both raster formats storing a grid of pixels, while SVG is a vector format describing shapes mathematically. PNG compresses losslessly with DEFLATE and prediction filters and supports a full alpha channel.[1][2] WebP uses VP8-derived prediction with both lossy and lossless modes plus transparency, generally yielding smaller files than PNG for the same image.[3][4] SVG stores XML drawing instructions rather than pixels, so it has no fixed resolution.[5]
Resolution and Scaling
SVG scales to any size with perfect sharpness because shapes are recomputed at render time, which makes it ideal for logos and icons, but it cannot efficiently represent photographic detail.[6] PNG and WebP have fixed pixel dimensions and degrade when enlarged beyond them. The choice between the two raster formats and SVG therefore depends first on whether the artwork is a scalable graphic or a fixed-resolution image.
File Size and Compression
For pixel-based artwork, WebP's modern coding generally beats PNG on file size while preserving transparency, whereas PNG guarantees exact lossless pixels and the broadest compatibility.[4][2] An SVG's size depends on the number of shapes rather than display dimensions, so a simple icon stays tiny at any scale; a complex illustration with thousands of paths, however, can exceed the size of an equivalent raster image.[5]
Editability and Standardization
Because SVG is text-based XML, it can be edited in a code editor, styled with CSS, animated, and searched; PNG and WebP are opaque pixel arrays editable only as images.[5] PNG is defined by the W3C and IETF (RFC 2083) and ISO/IEC 15948; WebP by IETF RFC 9649; SVG by the W3C.[1][2][3] All three are supported by current major browsers.
Applications
SVG is used for resolution-independent graphics, logos, charts, and icons, and can be styled and animated with CSS.[5] WebP is used for web delivery of photographic or detailed raster images needing small files. PNG is used where guaranteed lossless reproduction, transparency, and universal support outweigh file size.[1]