Better support for images uploaded via ATTACHED_FILES

[codeling]

When uploading files via the ATTACHED_FILES property of a test, CDash (as of version 3.4.3, not tested with 3.5 RC's yet) currently always displays a .tgz-wrapped version of those files. It would be immensely helpful if images uploaded via this mechanism (.png, .jpg) were treated similarly as images uploaded via the CTestMeasurement mechanism - that they are shown directly on the test page.

This would avoid quite some extra effort on test writing side for having to upload images via the CTestMeasurement mechanism in order to have images show up directly in CDash (see also this cmake discourse post).

[zackgalbreath]

Thanks for taking the time to write this up (and the even more detailed discourse post linked above).

I'm okay with tracking this feature request here, but I think the actual code changes will probably end up in CTest, right?

[codeling]

I'm okay with tracking this feature request here, but I think the actual code changes will probably end up in CTest, right?

I am only a user of both CTest and CDash, so I don't really have any insights on where things would need to be changed in order to achieve this.
I'll gladly report this on CTest side if you say it is more appropriate there!