docx drawing blurred

I’ve got a .docx file created in MS Office with some drawings inserted as OLE objects. When I open this file in LO Writer, these drawing are very blurred, so the labels cannot be read etc. If I double-click the object, it opens in LO Draw correctly, with no blur or distortion at all. Also when the same document is saved as .doc in MSO, it is not distorted (or just very slightly) in LO Writer.

What can be done to show the drawings correctly in Writer?

I am using Linux Mint 17.1, LO 5.3, but the problem is not limited only to these versions.

How were the drawing created? Are they some kind of bitmap? Or vector format? Do they display at same scale (size) in Writer and Draw?