Reset Image Size 图片转换缩放

System.Drawing.Image imgOriginal = System.Drawing.Image.FromFile(originalImagePath);        //获取原图片的的宽度与高度        int originalWidth = imgOriginal.Width;        int originalHeight = imgOriginal.Height;               //定义缩略图片宽度和高度          int thumbnailWidth, thumbnailHeight;        //如果原图片的宽度与高度都小于缩略图片尺寸        if (originalWidth < thumbnailSize && originalHeight < thumbnailSize)        {            thumbnailWidth = originalWidth;  //宽度等于原宽度            thumbnailHeight = originalHeight;//高度等于原高度        }        //如果原图片宽度大于原图片的高度                      else if (originalWidth > originalHeight)        {            thumbnailWidth = thumbnailSize;  //宽度等于缩略图片尺寸            thumbnailHeight = originalHeight * thumbnailSize / originalWidth;  //高度做相应比例缩小        }        //如果原图片高度大于原图片的宽度        else        {            thumbnailWidth = originalWidth * thumbnailSize / originalHeight; //宽度做相应比例缩小            thumbnailHeight = thumbnailSize; //高度等于缩略图片尺寸        }        System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(thumbnailWidth, thumbnailHeight);        System.Drawing.Graphics graphics = System.Drawing.Graphics.FromImage(bitmap);        //设置缩略图片质量        graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;        graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;        graphics.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;                graphics.DrawImage(imgOriginal, 0, 0, thumbnailWidth, thumbnailHeight);               // 保存缩略图片        bitmap.Save(imageSavePath);

原文地址：http://www.cnblogs.com/insus/articles/2060601.html