Hi Stefan and Andreas,

With the latest incremental version of elog (a738232), I have noticed that when attaching a pdf file, the
.png thumbnail is not generated when the "upload" button is pressed - there is just the usual small line saying
what the latest attachment is.  If this happens, a subsequent attachment will force the generation of the
thumbnail for the *previous* attachment, and again no thumbnail for the latest attachment.

Submitting the comment will also generate the thumbnail.

As of yet, I cannot find any consistent pattern to this.  Also, it's hardly a disaster, but I have been fooled
when attaching a pdf file that subsequently turned out to be damaged and thus unreadable.