Read the manual.
Especially the part about a Heads Up Display otherwise known as a HUD.
The manual is a PDF file found in the Docs folder.
You don't put it in the ifused of the trigger.
You create and show the HUD via an FPI script. (AIMAIN of the Trigger Zone)
Here is an
;Artificial Intelligence Script
;Header
desc = HUD Display
;Triggers
:state=0:hudreset,hudx=50,hudy=90,hudimagefine=gamecore\text\lockeddoor.tga,hudname=ndisplay,hudhide=1,hudmake=display,state=1
:state=1,plrwithinzone=1:hudshow=ndisplay,state=2
:state=2,plrwithinzone=0:hudunshow=ndisplay,state=1
;End of Script
example of displaying a HUD.
State=0 is the part that actually creates the HUD in this example.
Take note of the hudname=ndisplay.
You can name it what you want, just remember to show/unshow it using that same name. (like states 1 and 2)
The hudx=50,hudy=90 (in state=0) set the HUD's location to be displayed on the screen in percentages.
This example places it in the center (hudx=50) near the bottom of the screen (hudy=90)
The gamecore\text\lockeddoor.tga is the path and filename of the hud in this example.
You will need to change that to reflect your image.
Hope this helps.