the program pastes an object from a bitmap image without the background on to another image.
the object image's background should be in one color :
white w
black k
red r
yellow y
orange o
green g
blue b
violet v
other u

form controls :

picturebox * 2
textbox * 2
listbox : from its little arrow add :
w
k
r
y
o
g
b
v
u
Button * 4 :
Button1 text property : Button1
Button2 text property : save image
Button3 text property : image to paste
Button4 text property : image for the object to be pasted on to

using the program :
choose the two images
in the text boxes input the x,y positions of the image from which the object will be pasted
x,y can be negative of values. the default values are (0,0)

click the letter representing the background color of the object image on the list box.

if you want the new image to save click the save image button and name the new image :
name.bmp

note : the speed of the program will lower for higher definition images, while the
accuracy will increase. orange, green, blue backgrounds worked best for me in that order.

Code:

Public Class Form1
    Dim r1, g1, b1 As Integer
    Dim ObjectBackground As Char = "w"
    Sub RGB_Values(ByVal inColor As Color, ByRef red As Integer, ByRef green As Integer, ByRef blue As Integer)
        ' returns value of red,green,blue in a pixel of a bitmap as integers
        red = inColor.R
        green = inColor.G
        blue = inColor.B
    End Sub
    Public Function getPixelColor(ByVal r As Integer, ByVal g As Integer, ByVal b As Integer) As Char
        ' r= red, g = green, b = blue
        Dim colorchar As Char
        If r > 245 And g > 245 And b > 245 Then
            colorchar = "w" ' white
        ElseIf r < 20 And g < 20 And b < 20 Then
            colorchar = "k" ' black (kuro in japanese)
        ElseIf r > g And g > b And g < 100 Then
            colorchar = "r" ' red
        ElseIf r > g And g > b And g > 200 Then
            colorchar = "y" ' yellow
        ElseIf r > g And g > b And 100 < g < 200 Then
            colorchar = "o" 'orange
        ElseIf (g > r And r > b) Or (g > b And b > r) Then
            colorchar = "g" 'green
        ElseIf b > g And g > r Then
            colorchar = "b" 'blue
        ElseIf (b > r And r > g) Or (r > b And g < 20) Then
            colorchar = "v" ' violet
        Else
            colorchar = "u" ' yet undefined
        End If
        Return colorchar
    End Function
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim px As Integer = 0 ' x,y positions from which the image object will be pasted
        Dim py As Integer = 0 ' on the main image
        Try
            px = TextBox1.Text
        Catch ex As Exception

        End Try
        Try
            py = TextBox2.Text
        Catch ex As Exception

        End Try
        Dim I2 As Bitmap ' Image with object to paste
        I2 = PictureBox1.Image
        Dim I1 As Bitmap ' Image to paste object on
        I1 = PictureBox2.Image
        Dim EdX As Integer = 0 ' end x,y positions of the object
        Dim EdY As Integer = 0
        For I = 0 To I2.Width - 1
            For j = 0 To I2.Height - 1
                RGB_Values(I2.GetPixel(I, j), r1, g1, b1)
                If getPixelColor(r1, g1, b1) <> ObjectBackground Then
                    If EdX < I Then
                        EdX = I
                    End If
                    If EdY < j Then
                        EdY = j
                    End If
                End If
            Next
        Next
        Dim minX As Integer = EdX
        If px >= 0 Then
            If minX > I1.Width - px - 1 Then
                minX = I1.Width - px - 1
            End If
        ElseIf minX > I1.Width - 2 Then
            minX = I1.Width - 1
        End If
        Dim minY As Integer = EdY
        If py >= 0 Then
            If minY > I1.Height - py - 1 Then
                minY = I1.Height - py - 1
            End If
        ElseIf minY > I1.Height - 2 Then
            minY = I1.Height - 1
        End If
        Dim stx As Integer = 0
        Dim sty As Integer = 0
        If px < 0 Then
            StX -= px
            px = 0
        End If
        If py < 0 Then
            StY -= py
            py = 0
        End If
        'paste the object without it's background on the main image
        For i = StX To minX + StX
            For j = StY To minY + StY
                RGB_Values(I2.GetPixel(i, j), r1, g1, b1)
                If getPixelColor(r1, g1, b1) <> ObjectBackground Then
                    I1.SetPixel(px + i - StX, py + j - StY, I2.GetPixel(i, j))
                End If
            Next
        Next
        PictureBox2.Image = I1
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        ' saves the main image (the one on which the object is pasted)
        Dim I1 As Bitmap ' Image to paste object on
        I1 = PictureBox2.Image
        SaveFileDialog1.ShowDialog() ' open dialog
        SaveFileDialog1.Title = "Save an Image File"
        SaveFileDialog1.Filter = "Bitmap Image|*.bmp" ' set option for saved file extention
        I1.Save(SaveFileDialog1.FileName, Imaging.ImageFormat.Bmp)
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Try
            OpenFileDialog1.ShowDialog()
            Dim fs As IO.FileStream = New IO.FileStream(OpenFileDialog1.FileName, IO.FileMode.Open)
            Dim bitmap1 As Bitmap
            bitmap1 = Image.FromStream(fs)
            fs.Close()
            PictureBox1.Image = bitmap1
        Catch ex As Exception
            MsgBox("select an input path picture file")
        End Try
    End Sub

    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Try
            OpenFileDialog1.ShowDialog()
            Dim fs As IO.FileStream = New IO.FileStream(OpenFileDialog1.FileName, IO.FileMode.Open)
            Dim bitmap1 As Bitmap
            bitmap1 = Image.FromStream(fs)
            fs.Close()
            PictureBox2.Image = bitmap1
        Catch ex As Exception
            MsgBox("select an input path picture file")
        End Try
    End Sub

    Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
        ObjectBackground = ListBox1.SelectedItem
    End Sub
End Class