There is no way to make any of these inoffensive. The sign in question is not in any way racist, it's exactly to the point. The message intended is about religion and the state, the two are being mixed by the state with their "Year of the bible". This is already offensive.
The verse is from the bible, the picture, …an example from the history of the nation, founded supposedly on secular principles. It is not racist, not even close… it's just a historically correct reminder of things that have been sanctioned by the state, …corrected -> but still part and parcel of the bible the state wishes to celebrate. The image is not on characterizing a black person as inferior; on the contrary, it's pointedly illustrating a cruelty of bigotry that was inflicted on human beings, by human beings and still supported by a bible that, …unlike a constitution, …is not subject to amendments.
It's an image of an American slave.
It's a verse from a Christian bible.
Black people (all people) SHOULD be offended, not by this sign, but by this, and this alone.
Here's an example of this particular kind of hypocrisy that is quite germane:
This billboard was considered okay, and not offensive:
An atheist group in Ohiocontracted with a sign company to put this up:
They were refused on the grounds that the message was "obscene, unnecessarily offensive and/or not in the best interests of the community at large." Though, at first they were refused after the contract was accepted, with no explanation why.
This current issue isn't about black people asserting that they're rightfully offended, it's about Christian people asserting privilege, both in ignoring both the spirit and letter of the Establishment Clause, as well as the entitlement to be offended by biblical scripture, …only if expressed by non-Christians.