Andreu, You probably won't need to register a new datatype unless you want specific new features - the built in html datatype is probably what you need. Brief recipe: you'll probably need to wrap the tool with a python or other script because you'll want to write all the links to your outputs after they're generated as a legal html document as the contents of that html output file, and you'll need to pass the extra_files_path to the tool on the command line as a parameter so it knows where Galaxy will look when the user clicks on one of the links to the outputs you want to offer. The 3 rgQC files in your Galaxy tools/rgenetics directory are one example of how to create one html file containing dozens of other images and files in a complex layout - feel free to ask any specific questions if the code doesn't make much sense.. a) create an html datatype as the output from your tool and pass its extra_files_path as a parameter for the tool wrapper - see rgQC.xml b) write all ther output files into that extra_files_path - see rgQC.py c) write a web page (ie generate html code including a list of links to all your outputs) and write that as the contents of your html output file - see rgQC.py This html page will be displayed to the user when they click the eye icon - links will be followed into the extra_files_path and displayed. Note that the display is clever enough to look for the links in the extra_files_path - they don't need any path prepended - just the filenames you've written will be sufficient. I hope this helps - thanks for using Galaxy. . On Tue, Sep 14, 2010 at 8:52 AM, Andreu Alibés <aalibes(a)gmail.com&gt; wrote: