Clarification on thumbnail behaviour

[Julia Gilmore]

Hello wonderful DSpace world! 

We're hoping to clarify the behaviour of thumbnail generation on a DSpace 8.3 instance. A SAF package was imported (using SAFCreator) which included a number of known and unknown-to-DSpace file formats, many which were geospatial formats. In the SAF package, the bundle:thumbnail was assigned to a jpg image in the list. The bundle:original was set to reference the local desktop folder with the source files.

After the package was imported, we manually ran the filter-media command to check the results. We found the assigned thumbnail image showed for the item when it appeared in the search results and as a recent submission, but on the item itself, a black box appeared for the preview image, because the first file in the list was a .tfw file. When we manually edited the bitstream order and moved the .jpg file to the top, the desired image displayed on the item page (no more black box). We also noticed from running the command that DSpace generated thumbnails for all of tif and jpg files.

We would like to confirm if what we've observed is the correct behaviour, and why there is a difference between the thumbnail that shows on the results page and what shows on the item page. Does the bitstream you want to use for the simple item page thumbnail always need to appear first in the bitstream list when importing via SAF, regardless of what you set for the bundle:thumbnail? 

Thanks very much, 

Julia