According to the caption, this picture was taken with the Phoenix Mars Lander’s robotic arm and shows the underside of the vehicle.
This view from the north side of the lander toward the southern leg shows smooth surfaces cleared from overlying soil by the rocket exhaust during landing. One exposed edge of the underlying material was seen in Sol 4 images, but the newer image reveals a greater extent of it. The abundance of excavated smooth and level surfaces adds evidence to a hypothesis that the underlying material is an ice table covered by a thin blanket of soil.
Ice? It looks like home plate to me. :-)
Sorry for all the posts about the Phoenix mission. I just find the whole thing fascinating.
It’s certainly more interesting than whatever it is the talking heads channels think I should be paying attention to.