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Images are Missing when Using GetThumbnail Function

Dear Support,

I have a problem when exporting PPTX slides to images using the GetThumbnail function: one many (but not all) slide thumbnails thus produced, some images are missing.

For instance, here the exported thumbnails:
test_images_Slide1.jpg (59.2 KB)
test_images_Slide3.jpg (32.4 KB)

And here what it should look like:
Folie1.JPG (91.2 KB)
Folie3.JPG (77.8 KB)

What can I do about that?

I could upload you the PPTX file in question, so as to allow for reproducing the problem yourself (let me know where to upload the file).

The code I use is this (with global c_PresentationDocument = New Aspose.Slides.Presentation(glb.strPathSource & c_Filename)):

	Private Sub PPT_Save_Slides_in_Files(ByVal a_ppFile As String)
		' Export PPT slides as single-slide PPTXs and JPGs 
		Dim sImageName As String
		Dim img As Image
		Dim objLock As New Object

		Dim i As Integer = 1
		Dim strNumber As String = ""
		Dim filename As String = IO.Path.GetFileName(a_ppFile)
		filename = filename.Substring(0, filename.Length - 5)

		Try
			For Each slide As ISlide In c_PresentationDocument.Slides

				Console.WriteLine("Generating thumbnail for slide " & i & "/" & c_PresentationDocument.Slides.Count)

				strNumber = i.ToString

				' Insert leading zeros
				While strNumber.Length < c_PresentationDocument.Slides.Count.ToString.Length
					strNumber = "0" & strNumber
				End While

				' Export thumbnail
				sImageName = filename & "_Slide" & strNumber & ".jpg"

				Dim bmp As Bitmap = slide.GetThumbnail(1.33, 1.33)

				bmp.Save(glb.strPathTarget & sImageName, System.Drawing.Imaging.ImageFormat.Jpeg)

				i = i + 1

			Next ' slide

		Catch ex As Exception
			glb.ExceptionHandling(ex.Message, "#0610", AddressOf Rollback)
		Finally

		End Try

	End Sub

@drcarl,
Thank you for reporting the issue.

Please test your results using the latest version of Aspose.Slides if it is possible. If the issue persists, please share the folowing data:

  • presentation file
  • OS version on which the code was run
  • .NET target platform in your app
  • Aspose.Slides version you used

You can zip the files and upload them here.

Hey Andrey.

Kind Thanks for your prompt reply.

The Aspose.Slides version I’m using is 22.2.0
Operating system: Windows 11
Target: .NET Core 3.1

I have uploaded the PPTX file in question, along with the thumbnails produced by Aspose.

Can you reproduce the problem?

test_images.zip (518.7 KB)
test_images.zip (518.7 KB)

@drcarl,
I added a ticket with ID SLIDESNET-43101 to our issue tracking system. Our development team will investigate this case. We will inform you of any progress.

@drcarl,
Our development team investigated the issue. Unfortunately, we cannot reproduce it on our side. Please try to isolate the problem and provide additional information to help us to catch and fix the bug.

Strange. With us, the problem persists, and can be readily reproduced.

Anyway, here is our OS/software configuration:

Windows 11 Pro 21H2 22000.556, 64 bit
VB .NET Core 3.1
Aspose.Slides Version 22.2.0
Microsoft Visual Studio Community 2019, Version 16.11.11
Microsoft .NET Framework 4.8.04161
Region: Germany, German (DE)

Did you try it with the PPTX example file I provided?
With the same, or comparable, OS/software configuration?

Can you give me an example of the thumbnails you produced while trying to reproduce this issue?

@drcarl,
We tested the issue according to the information you provided above using the presentation you provided. Our results looks like this: images.zip (207.0 KB)

I’ve passed this additional information to our development team. We will check the issue again.

@drcarl,
Unfortunately, our developers have not been able to reproduce the image issue yet. Could you please share a sample project that allows us to see the problem?