PDF gallery

Thanks for your question, which is a variation on this earlier topic:

Att Tag Not Working

The default MIME Type for [mla_gallery] queries is image. Since you are trying to compose a gallery of PDF documents you need to add post_mime_type=application/pdf or post_mime_type=all to your shortcode.

I hope that will get you the results you need. I am marking this topic resolved, but please update it if you have any problems or further questions about composing galleries for PDFs and other MIME Types. Thanks for you interest in the plugin.