Hubble "Staircase" effect?

[Shilly]

Hi, I was just wondering why some of the older Hubble pictures have a staircase effect on them? Any help would be appreciated! Example below

edit: refer to examples in post #3

[Ich]

http://de.wikipedia.org/w/index.php?title=Datei:Jfader_hubble.jpg&filetimestamp=20081226211828

[Shilly]

OHHH so each quadrant is taken with a separate camera? Why is it no longer like this?

http://upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Bok_globules_in_IC2944.jpg/592px-Bok_globules_in_IC2944.jpg

http://upload.wikimedia.org/wikipedia/commons/thumb/a/a8/STSci-PRC01-33_omega_centauri.jpg/600px-STSci-PRC01-33_omega_centauri.jpg

[Ich]

Because they changed the WFPC2 (http://en.wikipedia.org/wiki/Wide_Field_and_Planetary_Camera_2) for the WFPC3 in 2009.