You will find version of products in the jar’s manifest file. All last versions of Aspose.Slides products also have version and release date in the file name. For example: aspose-slides-jasperreports-1.3.0-20100323.jar
Support for JasperReports 3.7 was added in the version 1.3 of Aspose.Slides for JasperReports. Also there was added better processing of images with transparency. There are additional checks for image type, codec and etc.
I have one idea. Please investigate your reports and check if there are any links to external non-existing images or may be empty images loaded from database. In case it has some then you probably should fix it and additional check with workaround should be added to Aspose.Slides. In case all images are correct then provide more detailed information about images used in the reports. For example type of images, transparency and etc. It’s better if you provide also example of the report with data.