Keep some info across translations

Hi,

some of my users found it annoying to translate images and not have the original information (the image itself and the taxonomy, or gallery) in the translated items. These are often the same in the original and the translated version, so I devised a patch to keep that info across translations. Here it is, hope it makes it to the next version of Image, or at least can be of use to some.

Thanks for the module,

Albert