With the move of the HTML system preferences to the news tool, adding a logo to the OPAC will require that you add a news block for it to each installed language. If you add languages later on, you will always need to test and remember. This adds quite a bit of extra maintenance as there appears to be no fallback option. It would be nice if we could define that something should show for 'all languages' or as a 'fallback' if there is no other content for the language defined.
Another option might be a "Copy to other languages" option.
Having now dug through the code a little.. I must admit the News system feels really weird
Done on bug 24387. *** This bug has been marked as a duplicate of bug 24387 ***