Image files loading issue

p5.js Beginners
4

I figured out, that if I comment out anything having to do with the image, the code works in the browser (Firefox):
Here´s what happens in a smaller test example: I used a coding example from the MAKE: Getting started with p5.js book. They mention some things having to do with servers, but don´t go into detail and commence with the coding example below…

var img;

function preload() {
img = loadImage("lunar.jpg");

}
function setup() {
createCanvas(480,120);
}

function draw() {
image(img, 0, 0);
}

The .jpg-file is copied into the project folder and is located besides the sketch.js file.

Here´s the consoles error:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at file:///C:/Users/Dandimite/Desktop/p5/Lunar_pic/lunar.jpg. (Reason: CORS request not http).

TypeError: NetworkError when attempting to fetch resource.

THX for help!!
BX