ShowImage diplays general error when image cannot be loaded by Translator

[grexe]

ShowImage is very lazy on indicating the cause of error when an image cannot be displayed because a suitable translator is not installed or it cannot open the file.

As a user, I'd like to know:

• if the file is indeed not found / cannot be opened for whatever reason
• if I am missing a suitable Translator for that file at all, or
• if I *do* have a Translator for that image file type installed but it still cannot open/handle that image.

Currently, I get a Windows-worthy super generic catch-all error message that is very unhelpful. This can be easily improved, as ShowImage knows the real cause.