If you're trying it on a server with GS2 enabled.
NPC Code:
//#CLIENTSIDE
function onCreated() {
show();
}
function onCompusDead() {
hide();
sleep(2);
show();
}
The graphic should automatically block which means the blockagain command really isn't needed so long as there is never a dontblock command (which also isn't needed due to the fact that once an image is hidden it shouldn't block you). HOWEVER due to the fact that some players like to delete images to bypass the the doors and get straight to the link you may want to set the shape of the image and insert the dontblock and blockagain commands.
Just incase you're working on a server that for some odd reason is scripting in GS1 instead of GS2 (All new servers should be scripting in GS2, it is much more efficient and there are tons of new features so if you are scripting in GS1 then I suggest you talk to the manager of your server and have him start converting the scripts you guys have already done into GS2) then here:
NPC Code:
if (created) {
show;
}
if (compusdead) {
hide;
sleep 2;
show;
}