An image node that allows more external control than the standard Image node. It uses the Projection nodes to determine how the image will be attached to the surface. A Projection node isn't needed for intrinsic Object UVs so the Image Sampler's Color output can be plugged straight into the Color Input on a primitive shape.
Invert Alpha inverts the alpha portions of the image so that the alpha region becomes solid and non-alpha becomes transparent.
Invert Color inverts the color of the image.
2019.1 brings separate color channel outputs to the Image Sampler node.