Images will not display

We've setup Omeka 2.1.2 and I'm having trouble with a few things. Images that are uploaded will not display in any way. Any place the image itself is supposed to be, there is a link to the file (the link does work). When adding images as files to an item, the generic file icon is shown instead of a thumbnail. Imagemagick is installed and Omeka reports that the path to it works.

This is a new fresh install with almost nothing in it. But I can't get the images to work. Am I missing a setting somewhere?

I checked thumbnails, square_thumbnails and fullsize directories, and they are all empty. Originals directory has the files that I uploaded. So I think this means that ImageMagick is not working properly, even though we have the correct path entered into Omeka settings (test button does work). Anyone have suggestions on why ImageMagick is not working or what I can do to fix it?

Are the images reachable from an empty web browser? As in, when you add the image file's url to the address bar, does the browser display the image from the internet?

Yes, they were. I had my server admin rebuilt ImageMagick and now everything is working as expected.

I'm having a similar issue.
Since updateing to 2.2.2 version,
some of the pdfs have a "blank" thumbnail image.
I've checked it...and it is not missing... but simply blank.
How to get around that?