Was it ever confirmed that you weren't able to load hdfs files? I was under the impression that you couldn't load images from HDFS locations, but you could load series. In the documentation Input Formats document, under series it says, "Both text and binary data can be loaded from a single file or multiple files, stored on a local file system, a networked file system, Amazon S3, or HDFS." (http://thunder-project.org/thunder/docs/tutorials/input_formats.html
I'd also be interested to know the answer to this question as well or why it wasn't able to be loaded. I will potentially be shifting my data to an institutional cluster running hadoop that would be very applicable for this question.