i use SlideEx.getThumbnail(1f,1f), but result is not correct.
Image miss something.
One image have even a Evalution Message about Aspose.Metafiles.
I have worked with the presentation file shared by you and have observed the text missing in the generated thumbnails. However, if I select some other back ground shape color for the text regions then the generated thumbnail includes text inside it. As far as issue of missing smart art objects is concerned, I regretfully inform you that currently rendering of smart art objects is not supported for Aspose.Slides for Java. An issue with ID 18363 has been created in our issue tracking system to resolve the issue of missing text in slide thumbnail. A separate issue with ID 18364 has been created as a new feature request in our issue tracking system to provide smart art rendering support in Aspose.Slides for Java. This thread has been linked with both of these issues so that you may be automatically notified, once the issue is resolved.
We are sorry for your inconvenience,