Hi, 1. Does any one know how to crop a image using GIL? 2. The IO extension seems not support to serialize a image binary data to memory, how to do that using GIL? (read png -> do some stuffs... -> write png to char* buffer not file.) 3. Is there any one good performance image comparison algorithm to compare two images by GIL? I am using ImageMagick to do that now. It try to compute Mean Absolute Error for two images, how this can be done by GIL? Thanks for your answer, I am try to adopt my old ImageMagick's code to GIL, I like elegant design of GIL but I am a newbie. Thanks for you patient to answer my questions. :) -- View this message in context: http://www.nabble.com/Some-problems-about-GIL-tp20526156p20526156.html Sent from the Boost - Users mailing list archive at Nabble.com.