[1.5.2] Use photo capture time as caption: Use an international denotation?

Use photo capture time as default caption while uploading is a very useful option. However, it uses the date format in the user's locale. This is perhaps appropriate in most cases. But for my gallery, I need to make captions readable by both English and Chinese visitors. So if I upload using an English locale, my Chinese readers will not be able to read the caption, and vice versa.

Is there someway to use an international denotation instead of a "translated" format? YYYY-MM-DD HH:MM:SS looks fine to me.