Mmm. Could be. There may once have been standing liquid water in these regions, and there are many who really want there to once have been lakes, seas, and oceans on Mars, but it is very difficult to create conditions on the surface of Mars that would allow substantial amounts of liquid water for more than a very short time -- at least on planetary time scales.

The problem is that Mars is cold. The problem is compounded by the fact that Mars has always been cold at the surface -- except during impact and volcanic events in relatively localized areas.

Signs are, in fact, that the surface of Mars is as warm now as it has ever been, perhaps warmer now than in most of its history -- and it is still (usually) very, very cold.

It is unlikely, I think, that large bodies of liquid water would form and persist on the surface. On the other hand, a warm subsurface could host lots of liquid water, and under some circumstances, that water could be forced to the surface, where, under a cap of ice -- which would likely form very quickly -- it could flow and pond much like rivers, lakes, and seas on Earth. At least for a while.

If the circular formations in these images are mostly not impact craters but instead are the results of internal forces, then I think it would indicate a warm an active subsurface, somewhat like that of the Earth.

And that would be interesting!

Cheers, BFelix