'...        
For Each DR As DataRow In DT.Rows
            Do Until MyTaskCounter < 100
                Application.DoEvents()
            Loop
 
            RunAsync(DR)
 
        Next
 
    End Sub
 
 
    Async Sub RunAsync(DR As DataRow)
 
        Try
            MyTaskCounter += 1
            Await Task.Run(Sub()
                               Set_ImageHash(DR)
                           End Sub)
        Catch ex As Exception
        End Try
        MyTaskCounter -= 1
    End Sub

Joachim