Hi,
when i add a pptx file to confluence 7.3.4 the preview is without spaces.
Similar issues suggest to read this or to install some packages (linux related), but that did not help. I tried different fonts and the ppt format, but the issue remains. Confluence is hosted on a windows machine.
left -> Powerpoint 2010
right -> Confluence

When i use drag & drop the small preview is wrong, but it shows correctly when i click on it to view the full presentation.

I know it worked some versions ago, but not which exactly...