Columns in images that are identical should be assigned the same value

[rylid-umil]

In the visualizer for custom images, columns that have the exact same pixels as another column should be assigned the exact same value (leftmost prioritized, set as the guide vlue), and could be a toggleable option

For example, in this square, all the values would be identical because each row is the same. Its kind of a niche threshhold because most images will never have the same columns of pixels, but still