unfortunately the descript.ion is an old standard and has no specified way to encode non ansi chars for this reason gPhotoShow doesn't attempt to convert what it reads from there.
After reading your message I changed a parameter in the function that reads the descript.ion, now it checks whether the file has UTF-8 or UTF-16/UCS-2 BOM, if one is present the text is converted appropriately if not present it works as before (only ansi text).
This means that to display Russian text you need to load descript.ion with Notepad++, choose Encoding->Encode in UTF-8 and save.
About .gprop files. gPhotoShow saves them as UTF-16/UCS-2/Unicode but if you edit them with an external editor you must save them as UTF-16/UCS-2/Unicode with BOM (UTF-8 in this case is not supported). Again you can do it with Notepad++.
Here is the updated gPhotoShow Pro version:http://www.gphotoshow.com/files/gpsprosetup-722-756.exe
UTF-16/UCS-2/Unicode are different names for the same encoding.
Without BOM gPhotoShow is not able to convert char encoding correctly.
Notepad++ is a free text editor, it is very useful to convert text from one encoding to another or to save it with a specific encoding.