Hello Ram,
Your Image has been placed in header section as logo? While exporting to Excel, you will be able to see only data in report part, header part will be ignored. I am not sure if this has been corrected in latest versions, but I am sure that in your 3.1 version header data will not come to excel.
If your image is in header, as a workaround you can keep your image and header objects in report section and I think exporting will take image also to excel.
Regards,
Nikhil Joy