what is this picture conveying, what is the author trying to say? And how does this picture relate to what happening in this period (I think it was the lynching)

It's conveying racism and inequality amonst skin color. During this period slavery was most likely normal or poc were definitely treated differently. The two white men with guns at this time were like most people who were white, putting down pocs since they believed that pocs were mean't to be slaves. Nobody was even trying to help the man who could've been guilty; instead they most likely hung him since he was a poc.

the  wilmot proviso  was designed to eliminate  slavery  within the  landacquired as a result of the mexican war (1846-48). fearing the addition of a pro-slave territory, pennsylvania congressman david  wilmot proposedhis amendment to the bill.