I have encountered an issue with converting certain ppt files to pdf. During the conversion process an exception will get thrown on certain ppt files that say “Unknown pixel format.” I have attached a test app along with the 2 problem ppt files that are affected by this issue in the project folder.
Aspose slides 18.3.0.0
PixelFormat.zip (1.4 MB)
I have worked with the presentation file shared by you using Aspose.Slides for .NET 18.12 on my end and have not been able to observe the issue. I request you to please try using the specified version on your end. I have also attached generated PDF as well for reference.
PPTTest.pdf (30.7 KB)
It appears the document converts but, the image is missing from the final PDF. I also tried locally with enabling the license.
Example before and after.
conversion.png (17.5 KB)
I have observed the image shared by you and an issue with ID SLIDESNET-40808 has been created in our issue tracking system to further investigate and resolve the issue. This thread has been linked with the issue so that you may be notified once the issue will be fixed.