Thank you for the feedback on the PDF viewer.
When it comes to the null-reference exception, this is an unexpected behavior and we would appreciate if you could open a support ticket and attach some of the files that can be used to reproduce the issue.
As for the fact that some files are not displayed properly, this may be due to the fact that support for cross-reference stream was not implemented in the Beta release. In the upcoming Service Pack in mid-January, an official version of the control will be shipped which will include support of cross-reference streams.
When it comes to the import of images, currently only JPEG images can be imported. We have this issue on our to-do list as well.
I hope this answers your questions.
All the best,
the Telerik team
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