Bitmap issue - parameter is not valid & out of memory - exception

Question

I have a vb.net program that tries to take a bunch of images and change the resolution to a smaller size. My program tries to loop through all the images to accomplish this using this code below. I've posted both the function and the button click that calls it. It will go through 27 images fine but on the 28th will error out with "parameter is not valid".
Friend Shared Function SetResolution(ByVal sourceImage As Image, ByVal resolution As Integer, ByVal strFullPath As String) As Image
Try
Dim reduction As Double = resolution / CInt(sourceImage.HorizontalResolution)
Using newImage As New Bitmap(sourceImage.Width, sourceImage.Height, sourceImage.PixelFormat)
newImage.SetResolution(resolution, resolution)
Dim outImage As New Bitmap(sourceImage, CInt(sourceImage.Width * reduction), CInt(sourceImage.Height * reduction))
Using g As Graphics = Graphics.FromImage(newImage)
g.InterpolationMode = Drawing2D.InterpolationMode.HighQualityBicubic
g.DrawImage(outImage, 0, 0)
g.Dispose()
End Using
newImage.Dispose()
Return outImage
End Using
Catch ex As Exception
MsgBox("An error occurred with the SetResolution function - " & ex.Message)
End Try
End Function
Private Sub btnSaveImages_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveImages.Click
Dim S As String
Dim Box As MsgBoxResult = MsgBox("Any previous images saved to this location will be overwritten. Are you sure you want to save these images?", MsgBoxStyle.YesNo)
Dim strFolderPath As String = ""
Dim strFolderReportPath As String = txtBrowse.Text & "\Report"
'Try
'the Report folder may not exist. Create it if needed.
If Not Directory.Exists(strFolderReportPath) Then
Directory.CreateDirectory(strFolderReportPath)
Else
'if it does exist then we need to either delete the folder or clean out all the files.
Dim downloadedMessageInfo As System.IO.DirectoryInfo = New DirectoryInfo(strFolderReportPath)
For Each file As FileInfo In downloadedMessageInfo.GetFiles()
file.Delete()
Next
For Each dir As DirectoryInfo In downloadedMessageInfo.GetDirectories()
dir.Delete(True)
Next
End If
If Box = MsgBoxResult.Yes Then
If lstSelectedImages.Items.Count <> 0 Then
For Each S In lstSelectedImages.Items
'MessageBox.Show(S)
Dim image1 As Image = Image.FromFile(S)
Dim strFilePath As String = Path.GetDirectoryName(S)
strFolderPath = Path.GetDirectoryName(S)
Dim strFileName As String = Path.GetFileName(S)
Dim strNewFolder As String = strFilePath & "\Report\"
strFileName = strFileName.Replace(".", "-Report.")
Dim strFullPath As String = strFilePath & "\Report\" & strFileName
image1 = SetResolution(image1, 50, strFilePath & "\" & Path.GetFileName(S))
'the Report folder may not exist. Create it if needed
If Not Directory.Exists(strNewFolder) Then
Directory.CreateDirectory(strNewFolder)
End If
image1.Save(strFullPath, System.Drawing.Imaging.ImageFormat.Jpeg)
image1.Dispose()
image1 = Nothing
Next
Dim di As New DirectoryInfo(strFolderReportPath)
'PopulateReportViewer(lstSelectedImages)
PopulateReportViewerByDir(di)
lblImageFolderLocation.Text = "Image Location: " & strFolderReportPath
MsgBox("Images saved to " & strFolderReportPath)
Else
MsgBox("Please select images to be saved into the Selected Images list box", MsgBoxStyle.Information)
End If
Else
End If
tbSelectCompressImages.TabPages.Add(TabPage2)
tbSelectCompressImages.SelectedIndex = 1
'Catch ex As Exception
' MsgBox("An error occurred with the Save Images button - " & ex.Message)
'End Try
End Sub
So, I was pretty stumped with that and decided to make a small change to how the bitmap was created to below. I was able to get 28 images saved again but this time received an out of memory error for the Graphics.FromImage line.
Dim newimage As Bitmap = DirectCast(Image.FromFile(strPath), Bitmap)
Does anyone know why this is occurring looking at my code. Or, is there code somewhere that I can get to set the resolution for an image so that the memory stamp is much smaller?
thanks.

Answer 1

but we can't see what you do with sourceImage and outImage.
image1 = SetResolution(image1, 50, strFilePath & "\" & Path.GetFileName(S))
You are re-assigning the image1 variable with this statement. Problem is, you never disposed the original image1. It is also a major guess why you are passing a path name, the method doesn't use it at all. So somewhat more sane code that doesn't forget to dispose ought to look like this:
Dim newImage = SetResolution(image1, 50)
image1.Dispose()
image1 = newImage