I have an integer variable that represents the number of limbs the player have. When player loses a limb, the number in the integer decreases by 1, and with each new number i want a picture on the widget change too, so if integer is at 5, then the little person on the pic has all limbs; if the number is 4, then the image widget should pick up the next image with one limb missing an show that instead, and so on and so forth.
Now you can use the image in the graph tab of the widget. I made a simple node system for it. It may look a bit different for a normal image but the principle is the same.
Get your character and the variable from it
The Select node can choose an image based on the INT value. You can add pins if you have more than 2 images.
Set the style of the image.
This is just one of many ways to do it. Hope it gives you the right direction.