Portable Network Graphics. Portable Network Graphics (PNG /ËpÉªÅ/) is a raster graphics file format that supports lossless data compression. PNG was created as an improved, non-patented replacement for Graphics Interchange Format (GIF), and is the most widely used lossless image compression format on the Internet.
The slavery in the United States was a paradox because it contradicted the American ideal of freedom C. Slavery is one the black chapters in mankind history. It shows barbarian, immorality and misunderstanding.
The cheap answer is slavery: the existence of lots of conscript labor retarded industrial development in the ancient world -- with so much extra labor available at whip-reach, there was little incentive to invest in productivity and also there was a smaller working class to whom you could conceivably sell products.