Hi Beer Mohammed,
Thanks for inquiring Aspose.Slides.
I have observed the quireies shared by you and will adress them indipendently.
1. Aspose generates the ppt by default. How to export the ssrs reports to ppt in our customized ppt template?
Aspose.Slides for Reporting Services does not support exporting the presentation to customized PPT templates. However, you can use Aspose.Slides for .NET for applying new template to exported presentation.
2. We exported SSRS report to ppt in a new presentation, but we have an issue that the report image is not fit in ppt slide. It is going beyond the slide. How to ensure that ppt generated has the full size image properly displayed?. [For reference see the attached PPT].
I have observed the presentation shared and like to share that the issue is due to wrong report size. The report size is exceeding default slide size. The default slide size is 10'' x 7.5'' and you must set the report size accordingly to avoid overflowing.
3. And watermark for license is not going up after we put 3 lines of code to remove water mark.
I guess you are setting license improperly in your application. Please use the guidelines shared over following link for applying Aspsoe.Slides for Reporting Services license. I also like to add that one cannot use Aspose.Slides for .NET license with Aspose.Slides for Reporting Services.