Uploading Damages

Whenever I upload PowerPoint Math documents to My Contents, the following types of damages occur:
(1)An English letter, turned into Greek by choosing the font as 'Symbol', is replaced by '?'
(2)In the figures drawn using drawing tools, certain lines change their direction.
(3)In the same slide, if there are different objects, some of them are left out, especially if their boundaries overlap.
To avoid such damages, this is what I sometimes do:
When a slide is finalized, select all, copy, and paste in Paint or Photoshop. After making any necessary changes, save it as a JPEG image in some folder. Then insert it into the slide.
One disadvantage of this procedure is that the background format changes.
Please suggest any other way out.

Tags: Uploading, Math Documents, Figures, Objects.