I think Mono is right
You might want to look at the PDF structure (use a demo copy of Adobe Acrobat X)
You might discover that you image is in fact a layer in your document. Possibly the document is missing the text layer or that is not accessible to you.
When I run into problems of this kind I always try to "clean" the PDF by saving it again from Adobe Acrobat. This is giving you the highest number of options when it comes to PDF formats. Changing the format might also clean the PDF structure.
Another way to do it:
Did you try to annotate your document on the desktop? What was the result?
If you try that save the doc with the new annotation added to it and move the document back to the ereader. That might also fix the problem