Blank thumbnail images

The image files exist in /files/square_thumbnails and are displaying, but all the images are white squares.

The thumbnails that Omeka generates generally use the first page of a PDF, so if the PDF's first page is blank the thumbnail will be a white square. When I followed some links, the PDFs themselves didn't seem to be loading properly, which might also be part of the issue.


After some more digging around, it looks like the trouble is in how the derivatives are created. We usually use the imagemagick application, which in turn depends on ghostscript to work with jpeg2000 images.

So far, a colleague who has a more recent version of ghostscript than I do (9.06) can get the derivatives just fine, but I can't. Beyond that, we're a bit baffled, but it might be that updating ghostscript on your server will do the trick.

If that does the trick, you can then use the Derivate Images plugin to recreate the derivatives.