Byte array to image conversion

Question

I want to convert a byte array to an image   This is my database code from where I get the byte array   public void Get Finger print         try               using  SqlConnection thisConnection   new SqlConnection   Data Source     System Environment MachineName      SQLEXPRESS Initial Catalog Image Scanning Integrated Security SSPI                           thisConnection Open                string query    select pic from Image tbl     where Name      name                    SqlCommand cmd   new SqlCommand query  thisConnection               byte   image   byte    cmd ExecuteScalar                Image newImage   byteArrayToImage image               Picture Image   newImage                return image                      catch  Exception            return null      My conversion code   public Image byteArrayToImage byte   byteArrayIn        try               MemoryStream ms   new MemoryStream byteArrayIn 0 byteArrayIn Length           ms Write byteArrayIn  0  byteArrayIn Length           returnImage   Image FromStream ms true    Exception occurs here           catch         return returnImage      When I reach the line with a comment  the following exception occurs  Parameter is not valid   How can I fix whatever is causing this exception

User · Answer

try  UPDATE   MemoryStream ms   new MemoryStream byteArrayIn 0 byteArrayIn Length   ms Position   0     this is important returnImage   Image FromStream ms true

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Most of the time when this happens it is bad data in the SQL column  This is the proper way to insert into an image column   INSERT INTO  TableX   ImgColumn  VALUES    SELECT   FROM OPENROWSET BULK N C       Picture 010 png   SINGLE BLOB  as tempimg     Most people do it incorrectly this way   INSERT INTO  TableX   ImgColumn  VALUES   C       Picture 010 png

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You are writing to your memory stream twice  also you are not disposing the stream after use  You are also asking the image decoder to apply embedded color correction   Try this instead   using  var ms   new MemoryStream byteArrayIn         return Image FromStream ms

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Maybe I m missing something  but for me this one-liner works fine with a byte array that contains an image of a JPEG file   Image x    Bitmap   new ImageConverter    ConvertFrom jpegByteArray      EDIT   See here for an updated version of this answer  How to convert image in byte array

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In one line  Image FromStream new MemoryStream byteArrayIn

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public Image byteArrayToImage byte   bytesArr        using  MemoryStream memstr   new MemoryStream bytesArr                 Image img   Image FromStream memstr           return img

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First Install This Package       Install-Package SixLabors ImageSharp -Version 1 0 0-beta0007    SixLabors ImageSharp  1       1   https   www nuget org packages SixLabors ImageSharp     Then use Below Code For Cast Byte Array To Image     Image lt Rgba32 gt  image   Image Load byteArray         For Get ImageFormat Use Below Code    IImageFormat format   Image DetectFormat byteArray        For Mutate Image Use Below Code    image Mutate x   gt  x Resize new Size 1280  960

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You haven t declared returnImage as any kind of variable     This should help   public Image byteArrayToImage byte   byteArrayIn        try               MemoryStream ms   new MemoryStream byteArrayIn 0 byteArrayIn Length           ms Write byteArrayIn  0  byteArrayIn Length           Image returnImage   Image FromStream ms true             catch         return returnImage

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All presented answers assume that the byte array contains data in a known file format representation  like  gif  png or jpg  But i recently had a problem trying to convert byte  s  containing linearized BGRA information  efficiently into Image objects  The following code solves it using a Bitmap object   using System Drawing  using System Drawing Imaging  using System Runtime InteropServices  public static class Extensions       public static Image ImageFromRawBgraArray          this byte   arr  int width  int height                var output   new Bitmap width  height           var rect   new Rectangle 0  0  width  height           var bmpData   output LockBits rect               ImageLockMode ReadWrite  output PixelFormat           var ptr   bmpData Scan0          Marshal Copy arr  0  ptr  arr Length           output UnlockBits bmpData           return output            This is a slightly variation of a solution which was posted on this site

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This is inspired by Holstebroe s answer  plus comments here  Getting an Image object from a byte array  Bitmap newBitmap  using  MemoryStream memoryStream   new MemoryStream byteArrayIn       using  Image newImage   Image FromStream memoryStream           newBitmap   new Bitmap newImage   return newBitmap

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there is a simple approach as below  you can use FromStream method of an image to do the trick  Just remember to use System Drawing      using image object not file  public byte   imageToByteArray Image imageIn        MemoryStream ms   new MemoryStream        imageIn Save ms System Drawing Imaging ImageFormat Gif       return ms ToArray       public Image byteArrayToImage byte   byteArrayIn        MemoryStream ms   new MemoryStream byteArrayIn       Image returnImage   Image FromStream ms       return returnImage

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I d like to note there is a bug in solution provided by  isaias-b   That solution assume that stride is equal to row length  But it is not always true  Due to memory alignments performed by GDI  stride can be greater then row length  This must be taken into account  Otherwise invalid shifted image will be generated  Padding bytes in each row will be ignored      The stride is the width of a single row of pixels  a scan line   rounded up to a four-byte boundary    Fixed code   using System Drawing  using System Drawing Imaging  using System Runtime InteropServices   public static class ImageExtensions       public static Image ImageFromRawBgraArray this byte   arr  int width  int height  PixelFormat pixelFormat                var output   new Bitmap width  height  pixelFormat           var rect   new Rectangle 0  0  width  height           var bmpData   output LockBits rect  ImageLockMode ReadWrite  output PixelFormat               Row-by-row copy         var arrRowLength   width   Image GetPixelFormatSize output PixelFormat    8          var ptr   bmpData Scan0          for  var i   0  i  lt  height  i                          Marshal Copy arr  i   arrRowLength  ptr  arrRowLength               ptr    bmpData Stride                     output UnlockBits bmpData           return output            To illustrate what it can lead to  let s generate PixelFormat Format24bppRgb gradient image 101x101   var width   101  var height   101  var gradient   new byte width   height   3    bytes per pixel      for  int i   0  pixel   0  i  lt  gradient Length  i    pixel   i   3        var x   pixel   height      var y    pixel - x    width      gradient i     byte   x    double  width - 1    y    double  height - 1     2d   255       If we will copy entire array as-is to address pointed by bmpData Scan0  we will get following image  Image shifting because part of image was written to padding bytes  that was ignored  Also that is why last row is incomplete     But if we will copy row-by-row shifting destination pointer by bmpData Stride value  valid imaged will be generated     Stride also can be negative      If the stride is positive  the bitmap is top-down  If the stride is negative  the bitmap is bottom-up    But I didn t worked with such images and this is beyond my note   Related answer  C  - RGB Buffer from Bitmap different from C

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One liner   Image bmp    Bitmap   new ImageConverter    ConvertFrom imageBytes

[c#] Byte array to image conversion

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