The ExifWorks class

Public Class EXIFtest



    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim text2 As String = TextBox2.Text
        Dim text3 As String = Replace(text2, ".jpg", "")
        Dim ef As New ExifWorks(text2)
        Dim imgWithExif As Image = ef._Image
        ef.UserComment = TextBox1.Text
        imgWithExif.Save(text3 + "TAGGED.jpg")
    End Sub

    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click


        TextBox2.Text = ("C:\Users\Simon\Music\Pictures\Exif Tests\DSC_1845.jpg")
        PictureBox2.ImageLocation = TextBox2.Text



    End Sub

    Private Sub EXIFtest_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        TextBox2.Text = PictureBox2.ImageLocation
    End Sub
End Class

'This merges all 4 bitfields into the lowest byte...
Private Function GetInt32(ByVal B As Byte()) As Int32
    If B.Length < 4 Then Throw New ArgumentException("Data too short (4 bytes expected)", "B")
    Return B(3) << 24 Or B(2) << 16 Or B(1) << 8 Or B(0)
End Function

'This will work correctly.
Private Function GetInt32(ByVal B As Byte()) As Int32
    If B.Length < 4 Then Throw New ArgumentException("Data too short (4 bytes expected)", "B")
    Return BitConverter.ToInt32(B, 0)
End Function

Public ReadOnly Property ExposureTime() As Double
        Get
            If Me.IsPropertyDefined(TagNames.ExifExposureTime) Then
                '-- Exposure time is explicitly specified
                Return 1000 / (1000 * Me.GetPropertyRational(TagNames.ExifExposureTime).ToDouble)
            ElseIf Me.IsPropertyDefined(TagNames.ExifShutterSpeed) Then
                '-- Compute exposure time from shutter speed
                Return 1 / (2 ^ Me.GetPropertyRational(TagNames.ExifShutterSpeed).ToDouble)
            Else
                '-- Can't figure out
                Return 0
            End If
        End Get
    End Property

Public Overrides Function ToString() As String
    Dim SB As New System.Text.StringBuilder

    SB.Append("Image:")
    SB.Append("\n\tDimensions:        " & Me.Width & " x " & Me.Height & " px")
    SB.Append("\n\tResolution:        " & Me.ResolutionX & " x " & Me.ResolutionY & " dpi")
    SB.Append("\n\tOrientation:       " & [Enum].GetName(GetType(Orientations), Me.Orientation))
    SB.Append("\n\tTitle:             " & Me.Title)
    SB.Append("\n\tDescription:       " & Me.Description)
    SB.Append("\n\tCopyright:         " & Me.Copyright)
    SB.Append("\nEquipment:")
    SB.Append("\n\tMaker:             " & Me.EquipmentMaker)
    SB.Append("\n\tModel:             " & Me.EquipmentModel)
    SB.Append("\n\tSoftware:          " & Me.Software)
    SB.Append("\nDate and time:")
    SB.Append("\n\tGeneral:           " & Me.DateTimeLastModified.ToString())
    SB.Append("\n\tOriginal:          " & Me.DateTimeOriginal.ToString())
    SB.Append("\n\tDigitized:         " & Me.DateTimeDigitized.ToString())
    SB.Append("\nShooting conditions:")
    <big>SB.Append("\n\tExposure time:     " & "1/" & CInt(Me.ExposureTime.ToString("N2")))</big>

'-- Compute exposure time from shutter speed
                Return 1000 / (1000 * (1 / (2 ^ Me.GetPropertyRational(TagNames.ExifShutterSpeed).ToDouble)))

'Decimal metres of altitude.
    Public ReadOnly Property Altitude() As Double
        Get
            If IsPropertyDefined(TagNames.GpsAltitude) Then
                Dim altRef As String = "00"
                Try
                    Dim Ref As Byte() = GetProperty(TagNames.GpsAltitudeRef)
                    altRef = BitConverter.ToString(Ref, 0, 1)
                Catch ex As Exception
                End Try
                Dim alt As Rational = GetPropertyRational(TagNames.GpsAltitude, 0)
                Dim hgt As [Double] = alt.ToDouble()
                If Not altRef.ToString.Equals("00") Then                             'Above Sea Level = 0, below = 1
                    hgt = -hgt
                End If
                Return Format(hgt, "##,###")
            Else
                Return Double.NaN
            End If
        End Get
    End Property