there is another quick way to do do a pure "center item in image":
-select your item in whatever way you like
-type: ctrl-x, ctrl-v, ctrl-x,ctrl-v (yes, twice cut-paste)

=>The first cut-paste will put the item back on the same place, the second one will put it on the center of the image (I'm not sure exactly why but happened to see that accidentally).


Sébastien Barré.