Tron

The answer you're looking for is called 'paperdoll'. When you create an item at the very bottom is an option to put in a paperdoll. All of the paperdoll sprites go inside the /resources/paperdoll directory.
 

F12
Then you can find the screenshot in the 'client & editor/screenshots'

Yes there is. If you go into your server folder and open up colors.json you will find everything there. What you're looking for is in this block:
 
  "Combat": {
    "AddMana": "255,0,0,255",
    "Blocked": "255,0,0,255",
    "Cleanse": "0,255,0,0",
    "Critical": "255,255,255,0",
    "Dash": "255,0,0,255",
    "Heal": "255,0,255,0",
    "Invulnerable": "255,255,0,0",
    "LevelUp": "255,0,255,255",
    "MagicDamage": "255,255,0,255",
    "Missed": "255,255,255,255",
    "NoAmmo": "255,255,0,0",
    "NoTarget": "255,255,0,0",
    "PhysicalDamage": "255,255,0,0",
    "RemoveMana": "255,255,127,80",
    "StatPoints": "255,0,255,255",
    "Status": "255,255,255,0",
    "TrueDamage": "255,255,255,255"
  },

I think if you want to show it like a minimap type of thing you have to modify the source. Otherwise you can do a chat command that will show the in-game time.