This is just a post for the benefit to whom is experiencing the full GC issue caused by embedding images in docx.
 public static BinaryPartAbstractImage createImagePart(
			OpcPackage opcPackage,
			Part sourcePart, byte[] bytes)
...
explicitly invokded System.gc() which caused high CPU load and performance issue. To avoid high CPU load/frequent full GC, better to use 
public static BinaryPartAbstractImage createImagePart(
            OpcPackage opcPackage,
            Part sourcePart, File imageFile)
			
		
