.NET 圖片格式轉換

①bmp轉tif

Dim bmp As Bitmap = New Bitmap(f)

Dim strTifDescFile As String = "C:/abc.tif"

'黑白雙色圖片
Dim tifImageCodecInfo As ImageCodecInfo
tifImageCodecInfo = GetEncoderInfo(ImageFormat.Tiff)
Dim tifEncoderParameter1 As EncoderParameter
Dim tifEncoderParameter2 As EncoderParameter
Dim tifEncoderParameters As EncoderParameters
tifEncoderParameter1 = New EncoderParameter(System.Drawing.Imaging.Encoder.ColorDepth, 8)
tifEncoderParameter2 = New EncoderParameter(System.Drawing.Imaging.Encoder.Compression, EncoderValue.CompressionCCITT4)
tifEncoderParameters = New EncoderParameters(2)
tifEncoderParameters.Param(0) = tifEncoderParameter1
tifEncoderParameters.Param(1) = tifEncoderParameter2

bmp.Save(strTifDescFile, tifImageCodecInfo, tifEncoderParameters)

②圖片轉Byte（）

Dim bytes As Byte() = System.IO.File.ReadAllBytes("C:/abc.tif")

③以流的方式讀取磁盤上的文件

直接讀取文件，文件會被鎖死，無法對文件進行修改。以文件流的方式讀取，讀取後不會鎖死磁盤上的文件

Public Function readImageFileByFileStream(ByVal filePath As String) As Image
    Using reader As New System.IO.FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read)
        Return System.Drawing.Image.FromStream(reader)
    End Using
End Function

Dim img As Image = readImageFileByFileStream("C:/abc.bmp")
pictureBox1.Image = img