Question

I need to check a picturebox for a specific image. I know you can check if the picturebox is populated with an image…

If Not pictureBox.Image is Nothing Then

Else

End If

But in my case, I need to check this picturebox for an image I loaded earlier on in the process.

Here is the current code I’m using to load the image…

PictureBox1.Image = My.Resources.TestImage1

I thought by using the following code I could check the image name, but this apparently does not work.

If PictureBox1.Image = My.Resources.TestImage1 Then
  'do something
Else
  'do something else
End if

Suggestions?

Answer 1

Image does not have any knowledge of the file name or any other name that it has been loaded from. What you can do, however, is compare images pixel-by-pixel. Try this code:

Public Function AreSameImage(ByVal I1 As Image, ByVal I2 As Image) As Boolean
  Dim BM1 As Bitmap = I1
  Dim BM2 As Bitmap = I2
  For X = 0 To BM1.Width - 1
    For y = 0 To BM2.Height - 1
      If BM1.GetPixel(X, y) <> BM2.GetPixel(X, y) Then
        Return False
      End If
    Next
  Next
  Return True
End Function

Credit goes here.

A useful article I found when looking for this answer:

• Compare two images to find differences greater than a threshold value in VB .NET

This is how you can check if your images are less than 100% equal, i.e. similar.