Some but not all images are rotated 90 deg on the PC after copying a presentation from Mac (running OS 10.9.5 and PP Version 14.4.8 for Mac 2011) to PC (running win 8.1 64bit and PowerPoint 2013).
Ideas?

Just transfer all the pics you took to a a file in windows (as you would if you back up your iphone and ipad to your PC) and open the file in using Windows Office Picture Manager. This program is included as part the Microsoft suite

Choose to see the folder in "thumbnail view" the little box with 4 little rectangles on it right under the Shortcuts menu command. You will then see all the pics in the folder.
Now you can individually rotate pics or highlight a bunch of them and rotate them at once using the rotate button up on top.
Its a button with too little triangles on it. One of the triangles is laying on its side.
Then hit "save" and voila! All your pics are now saved right side up! I didn't experience any sacrifice in quality of the pics or any changes.

I hope this provides further clarity. These links have some add' info on Office picture manager-
http://office.microsoft.com/en-us/he...001001721.aspx

If this does not work then meta data be remove from the picture an then it can be manipulated.
check this link to know how to do it
http://www.labnol.org/software/remov...etadata/19588/