The former is petechiae-small size(pinpoint areas).
The latter is ecchymoses-bigger size.
In few days after that post I had a question from the www.usmleworld.com question bank and according to them, the differences between petechiae, purpurae and ecchymoses are based on their size. For some reason I taught that both petechiae and ecchymoses are some kind of purpura, because of their color. Too busy to check that facts. May be later on, and also I trust usmleworld, these guys really rock.
Yes, I did quick check. That is right.
1.petechiae-less than 0.5 cm
2.purpurae-from 0.5 to 1 cm
3.ecchymoses-more than 1 cm
So, on the first picture there is a combination of petechiae and purpurae.