The shrinking southern polar cap is shown at about 1 o'clock on the image. The talk on some of the forums is that there is a large dust storm visible on Mars now. I believe the arrowhead shaped area in the upper left of the image is the duststorm - on maps of Mars this area is normally a dark area and now shows a light area. Duststorms are common on Mars during the Martian summer and can occasionally obscure most of the planet's visible surface!