Copy field value on translation?

I am using (4.0.2). While translating I would like to copy the value of a field to the new translated object. This field should be changeable in translated language without modifying the original language. Because of that I can not use language independent fields. The problem I am trying to solve: I would like to translate an image without the need to upload the image-file again. But in case there is some text at the image it should be possible to replace the translated image by uploading another image-file.

I saw there is ITranslationCloner but I could not find an example on how to use it. Maybe somebody has an expample for that?