本文实例讲述了C#实现为一张大尺寸图片创建缩略图的方法。分享给大家供大家参考。具体实现方法如下：

public static Bitmap CreateThumbnail(string lcFilename, int lnWidth, int lnHeight) { System.Drawing.Bitmap bmpOut = null; try { Bitmap loBMP = new Bitmap(lcFilename); ImageFormat loFormat = loBMP.RawFormat; decimal lnRatio; int lnNewWidth = 0; int lnNewHeight = 0; //*** If the image is smaller than a thumbnail just return it if (loBMP.Width < lnWidth && loBMP.Height < lnHeight) return loBMP; if (loBMP.Width > loBMP.Height) { lnRatio = (decimal)lnWidth / loBMP.Width; lnNewWidth = lnWidth; decimal lnTemp = loBMP.Height * lnRatio; lnNewHeight = (int)lnTemp; } else { lnRatio = (decimal)lnHeight / loBMP.Height; lnNewHeight = lnHeight; decimal lnTemp = loBMP.Width * lnRatio; lnNewWidth = (int)lnTemp; } bmpOut = new Bitmap(lnNewWidth, lnNewHeight); Graphics g = Graphics.FromImage(bmpOut); g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic; g.FillRectangle(Brushes.White, 0, 0, lnNewWidth, lnNewHeight); g.DrawImage(loBMP, 0, 0, lnNewWidth, lnNewHeight); loBMP.Dispose(); } catch { return null; } return bmpOut; }

希望本文所述对大家的C#程序设计有所帮助。