How to change image Exif metadata

If you have Photoshop editable image, it write tag "Photoshop" to Exif information and change another Exif tag. Even you save image without Photoshop metadata, it means only absent XMP tag in result image.

To restore original exif metadata you need to use some programs and steps.

• (0) The best program to show and evaluate you Exif in GUI mode is XnView MP, screen of this program you can see above. XnView MP has two opportunity to change Exif - (1) Clear it at all, (2) changing timestamp. Any other operation with Exif need to more deep understanding..



• (1) To Show Exif and edit it in symbolic view or in hexadecimal view by HexEdit is useful a project ExifLibrary for .NET. Also this project contains a lot information about Exof metadata.



• (2) Best way to simple copy one Exit information to another is own code contained only some simple lines. Come below copy all exif information from IMG_0000.jpg to IMG_0001.jpg with excluding Trumbnail image.
  
  

     1:  Imports System.Drawing

     2:  Imports System.Drawing.Imaging

     3:  Imports System.Text

     4:   

     5:  Module Module1

     6:   

     7:      Sub Main()

     8:          Dim SourceImg As New Bitmap("E:\My-1\IMG_0000.jpg")

     9:          Dim TargetImg As New Bitmap("E:\My-1\IMG_0001.jpg")

    10:          For Each One As PropertyItem In SourceImg.PropertyItems

    11:              Dim Str1 As New StringBuilder()

    12:              Str1.Append(String.Format("{0:x2} :", One.Id))

    13:              For i = 0 To One.Len - 1

    14:                  Str1.Append(String.Format("{0:x2}", One.Value(i)))

    15:              Next

    16:              If String.Format("{0:x2}", One.Id) <> "501b" Then

    17:                  TargetImg.SetPropertyItem(One)

    18:              End If

    19:              Console.WriteLine(Str1.ToString)

    20:          Next

    21:          TargetImg.Save("E:\My-1\IMG_00011.jpg")

    22:   

    23:      End Sub

    24:   

    25:  End Module

  
  

  And in this screen I compare information from this my copier and ExifLibrary for .NET from CodeProject.

  
  
  
• (3) There are one way to change Exif (exept changing timestamp by Xnview MP) - this is ExifTool by Phil Harvey, ExifTool by Phil Harvey. But this is command line utilities with big and difficult usage. This is common help of this utis exiftool-help.txt, and this is list of exif tag it supported exit-tag.txt.
  
  
  
• Main problem after Photoshop edition, it changing JFIF tags in Exif metagata. For example before Photoshop I was 300 DPI, after edition 72 DPI.
  
  
  

  Therefore after copying information to editable image you have to use at least one ExifTool command "C:\Program Files\exiftool.exe" -JFIF:*Resolution=300 IMG_0001.jpg

  
  
  
• Another small addition issue need to solved is DateTime for image access. There are two way to solve this problem. (1) There are GUI utilities Attribute Changer
  
  
  

  (2) By own codes. This small function collect information about image to database and than change image timestamp.

  
  

     1:  Imports System.Drawing

     2:  Imports System.Linq

     3:  Imports System.Text

     4:  Imports System.IO

     5:   

     6:  Class Module1

     7:   

     8:      Dim Db1 As VbNetDataContext

     9:      Public Sub New()

    10:          Db1 = New VbNetDataContext()

    11:      End Sub

    12:   

    13:      Public Sub SetImageDate(SiteRoot As String, httpPrefix as string)

    14:          Dim DirName As String

    15:          Dim Count1 As Integer = 0, Count2 As Integer = 0

    16:          For Each One As Entrance In Db1.Entrances.OrderByDescending(Of Integer)(Function(X) X.i).AsEnumerable

    17:              Debug.Print(One.URL)

    18:              Console.WriteLine(One.URL)

    19:              Dim RelPath As String = One.URL.Replace("httpPrefix", "")

    20:              DirName = IO.Path.GetDirectoryName(RelPath)

    21:              For Each OneImage In Db1.Images.Where(Function(X) X.Folder.ToLower = DirName.ToLower).Where(Function(X) CDate(X.ArticleDate).AddDays(30) < X.Accessed Or CDate(X.ArticleDate).AddDays(30) < X.Created Or CDate(X.ArticleDate).AddDays(30) < X.Modified).AsEnumerable

    22:                  Try

    23:                      Dim ImagePath As String = (SiteRoot & OneImage.Folder & "\" & OneImage.Name).Replace("\\", "\").Replace("/", "\")

    24:                      Debug.WriteLine(ImagePath)

    25:                      If IO.File.Exists(ImagePath) Then

    26:                          Console.WriteLine(ImagePath)

    27:                          IO.File.SetCreationTime(ImagePath, One.CrDate)

    28:                          IO.File.SetLastAccessTime(ImagePath, One.CrDate)

    29:                          IO.File.SetLastWriteTime(ImagePath, One.CrDate)

    30:                          Count1 += 1

    31:                      Else

    32:                          Console.WriteLine("Not found " & ImagePath)

    33:                          Count2 += 1

    34:                      End If

    35:                  Catch ex As Exception

    36:                      Console.WriteLine(ex.Message)

    37:                  End Try

    38:              Next

    39:          Next

    40:          Console.WriteLine(Count1.ToString & " image modified." & vbCrLf & Count2.ToString & " image not found.")

    41:      End Sub

    42:   

    43:      Public Sub UpdateImageDateInDB(SiteRoot)

    44:          For Each OneImage In Db1.Images.Where(Function(X) CDate(X.ArticleDate).AddDays(30) < X.Accessed Or CDate(X.ArticleDate).AddDays(30) < X.Created Or CDate(X.ArticleDate).AddDays(30) < X.Modified).AsEnumerable

    45:              Try

    46:                  Dim ImagePath As String = (SiteRoot & OneImage.Folder & "\" & OneImage.Name).Replace("\\", "\")

    47:                  If IO.File.Exists(ImagePath) Then

    48:                      Debug.Print(ImagePath)

    49:                      Console.WriteLine(ImagePath)

    50:                      Dim CreationTime As Date = IO.File.GetCreationTime(ImagePath)

    51:                      Dim LastAccessTime As Date = IO.File.GetLastAccessTime(ImagePath)

    52:                      Dim LastWriteTime As Date = IO.File.GetLastWriteTime(ImagePath)

    53:                      OneImage.Accessed = LastAccessTime

    54:                      OneImage.Created = CreationTime

    55:                      OneImage.Modified = LastWriteTime

    56:                  Else

    57:                      Console.WriteLine("Not found " & ImagePath)

    58:                  End If

    59:   

    60:              Catch ex As Exception

    61:                  Console.WriteLine(OneImage.Folder & "\" & OneImage.Name & vbCrLf & ex.Message)

    62:              End Try

    63:          Next

    64:   

    65:          Db1.SubmitChanges()

    66:      End Sub

    67:   

    68:      Public Sub InitialCollectImageToDB(SiteRoot)

    69:   

    70:          Dim Files = Directory.GetFiles(SiteRoot, "*.*", SearchOption.AllDirectories).

    71:              Where(Function(X) X.EndsWith(".jpg") Or X.EndsWith(".gif") Or X.EndsWith(".png") Or X.EndsWith(".jpeg"))

    72:   

    73:          For Each OneFile In Files

    74:              Dim DirName As String

    75:              Dim FileName As String

    76:              Try

    77:                  Dim RelPath As String = OneFile.Replace(SiteRoot, "")

    78:                  DirName = IO.Path.GetDirectoryName(RelPath)

    79:                  FileName = IO.Path.GetFileName(RelPath)

    80:                  Dim Img As Drawing.Bitmap = New Bitmap(OneFile)

    81:                  Dim CreationTime As Date = IO.File.GetCreationTime(OneFile)

    82:                  Dim LastAccessTime As Date = IO.File.GetLastAccessTime(OneFile)

    83:                  Dim LastWriteTime As Date = IO.File.GetLastWriteTime(OneFile)

    84:                  Dim Exist = (Db1.Images.Where(Function(X) X.Name = FileName And X.Folder = DirName)).FirstOrDefault

    85:                  If Exist Is Nothing Then

    86:                      Db1.Images.InsertOnSubmit(New Image With {.Folder = DirName, .Name = FileName, .X = Img.Width, .Y = Img.Height, .Accessed = LastAccessTime, .Created = CreationTime, .Modified = LastWriteTime})

    87:                  End If

    88:              Catch ex As Exception

    89:                  Db1.Images.InsertOnSubmit(New Image With {.Name = FileName, .Folder = DirName})

    90:                  Console.WriteLine(OneFile & vbCrLf & ex.Message)

    91:              End Try

    92:          Next

    93:   

    94:          Db1.SubmitChanges()

    95:      End Sub

    96:   

    97:  End Class

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