🔍 图片对比（找不同）Image Compare (Find Differences)

使用说明与常见问题How-to & FAQ

「图片对比（找不同）」是什么？What is the Image Compare (Find Differences) tool?

在浏览器里对比两张图片：左右滑动对比、并排、差异高亮、闪烁切换和半透明叠加；统计不同像素的数量和比例、差异范围、最大差值和 PSNR，可设置容差忽略轻微压缩噪点，并下载差异图。图片不上传。Compare two images in your browser with a swipe slider, side by side, highlighted differences, blink or a semi-transparent overlay. It counts the differing pixels and their share, shows where the differences are, the maximum difference and PSNR, lets you set a tolerance to ignore slight compression noise, and you can download the difference image. Nothing is uploaded.

如何使用「图片对比（找不同）」？How do I use the Image Compare (Find Differences) tool?

在「图片对比（找不同）」中，选择或拖入文件，按需设置「查看方式」、「容差」、「尺寸」等选项，然后点击「交换 A / B」按钮即可。In the Image Compare (Find Differences): Choose or drop your files, set "View", "Tolerance", "Size", then click "Swap A / B".

差异是怎么计算的？How are differences calculated?

逐像素比较两张图片的红、绿、蓝和透明度，取最大的通道差值（0–255）。差值大于“容差”的像素算作不同，在差异图上用红色标出，颜色越深差别越大；相同的像素显示为浅灰色的原图，方便定位。同时给出不同像素的数量和比例、包含所有差异的矩形范围、最大差值和 PSNR（峰值信噪比，越高越接近，完全相同时为 ∞）。Each pixel's red, green, blue and alpha are compared and the largest channel difference (0–255) is used. Pixels whose difference is above the Tolerance count as different and are marked red on the difference image — the stronger the red, the bigger the difference — while matching pixels show as a light grey copy of the original so you can find your way. You also get the number and share of different pixels, the rectangle containing all differences, the maximum difference and PSNR (peak signal-to-noise ratio: higher means closer, ∞ when identical).

容差有什么用？What is the tolerance for?

把同一张图另存为 JPG、换个软件导出或调整过画质后，肉眼看不出变化，但很多像素会有 1–20 左右的细小差值。容差设为 8 或 24 可以忽略这些噪点，只显示真正的改动，例如设计稿的修改、截图里新增的文字。要检查两张图是否逐像素完全一致，请用 0。When the same picture is re-saved as JPG, exported by another program or recompressed, you can't see a change, but many pixels differ by roughly 1–20. A tolerance of 8 or 24 ignores that noise and shows only real edits, such as design revisions or new text in a screenshot. Use 0 to check whether two images are identical pixel for pixel.

两张图片尺寸不一样怎么办？What if the images are different sizes?

默认把 B 缩放到 A 的尺寸再比较，适合同一张图的不同分辨率版本（缩放本身会带来细小差值，可配合容差使用）。也可以选“左上角对齐”，按原始像素比较，超出另一张图范围的部分全部算作不同，适合检查裁剪或画布扩展。By default B is scaled to A's size before comparing, which suits different resolutions of the same picture (scaling itself adds small differences, so combine it with a tolerance). Or choose Align top-left to compare original pixels, where any area outside the other image counts as different — useful for checking crops or canvas changes.

各种查看方式怎么用？How do the views work?

左右滑动：在图上按住拖动分割线，左边是 A、右边是 B。并排：两张图左右放置。差异高亮：显示红色标注的差异图。闪烁切换：每 0.6 秒在 A 和 B 之间切换，适合发现位置轻微移动。半透明叠加：把 B 以可调的不透明度叠在 A 上。Swipe: drag the divider on the image — A on the left, B on the right. Side by side: both images next to each other. Differences: the red-marked difference image. Blink: switches between A and B every 0.6 s, good for spotting slight shifts. Overlay: B over A with adjustable opacity.

支持哪些格式？图片会上传吗？Which formats are supported? Are images uploaded?

支持 JPG、PNG、WebP、GIF（第一帧）、BMP、AVIF、HEIC 等浏览器能读取的图片，透明 PNG 的透明度也参与比较。单张最大 60 MB、1 亿像素。所有比较都在你的浏览器里完成，图片不会上传。JPG, PNG, WebP, GIF (first frame), BMP, AVIF, HEIC and other images the browser can read are supported, and transparency in PNGs is compared too. Up to 60 MB and 100 megapixels per image. Everything is compared in your browser; images are not uploaded.

有哪些选项可以调整？What options can I adjust?

「图片对比（找不同）」的设置：「查看方式」可选 左右滑动、并排、差异高亮、闪烁切换、半透明叠加（默认 左右滑动）；「容差」可选 0（任何差别都算）、8（忽略极轻微差别）、24（忽略压缩噪点）、64（只看明显差异）（默认 0（任何差别都算））；「尺寸」可选 尺寸不同时把 B 缩放到 A 的尺寸、尺寸不同时左上角对齐（默认 尺寸不同时把 B 缩放到 A 的尺寸）；「B 的不透明度」默认 50，范围 0–100；可选文件：常见图片格式（含 HEIC、HEIF、AVIF、WEBP）。改动任一选项后结果会按新设置重新生成。Settings in the Image Compare (Find Differences) — "View": Swipe, Side by side, Differences, Blink, Overlay (default Swipe); "Tolerance": 0 (any change), 8 (ignore tiny), 24 (ignore compression noise), 64 (obvious only) (default 0 (any change)); "Size": Scale B to A, Align top-left (default Scale B to A); "B opacity" default 50, range 0–100; files: common image formats (including HEIC, HEIF, AVIF, WEBP). Changing any option regenerates the result with the new setting.

「图片对比（找不同）」免费吗？需要注册吗？Is the Image Compare (Find Differences) free? Do I need an account?

「图片对比（找不同）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Image Compare (Find Differences) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.