DiffImg 是一款簡易的圖片比對工具。它以兩張同樣尺寸的圖片做為比較的基礎，若尺寸不同則無法比較，因為如果兩張圖片的尺寸不同，不必比較也知道它們的參數大多不同。總而言之，這款軟體可以比對不同檔名、不同圖檔格式、但圖片尺寸必須相同的兩張圖片。
它能夠精準顯示不同的區域，並提供平均誤差、最小誤差、最大誤差、標準差、方均根偏差、誤差個數 (像素)、誤差百分比 (像素) 等方面的數據供使用者參考。
§ 作業系統：Windows XP/Vista/7/8
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DiffImg 原文簡介：
DiffImg is a simple image comparison tool which takes two images with the same size as input. Some statistics are computed and the positions where pixel differs are displayed as a color mask.
This application uses OpenCV as backend so it can read and compare 8/16/24/32 bits images without problem but only single channel and RGB image has been take into account, so alpha channel isn’t supported.
Because it is written with Qt, it runs on Windows and Linux (MacOSX isn’t tested yet) and OS/2. It can read basic formats as BMP, PNG, JPG but also Tiff and OpenExR; it supports basic batch mode.