On the SEAD internal instance, there is inconsistency with regard to previews of files that are the same type. For example, some csv show preview of the file, some show the icon for spreadsheet; and yet others show the big black square. Same for .log.

Other files show nothing (not even medici logo) for example: http://sead.ncsa.illinois.edu/acr/#dataset?id=tag:medici@uiuc.edu,2009:data_HaLhD_QpVAvI-bph_isw4w

This file (mp4) also shows just a grey square: http://sead.ncsa.illinois.edu/acr/#dataset?id=tag:medici@uiuc.edu,2009:data_63t3cFbjgXqhkJ0gDblIEw

These are pretty minor and should not stop rollout of bigger tile display with new icons.