Check image width and height before upload with Javascript

Question

I have a JPS with a form in which a user can put an image:

    
Photo (max 240x240 and 100 kb):
    

        
      

Answer 1

    const ValidateImg = (file) =>{
        let img = new Image()
        img.src = window.URL.createObjectURL(file)
        img.onload = () => {
            if(img.width === 100 && img.height ===100){
                alert("Correct size");
                return true;
            }
            alert("Incorrect size");
            return true;
        }
    }