load html direct by browser vs load with IIS(Visual studio 2019)

I have a CSS file and HTML when I'm loading it directly by any browsers all my CSS load perfect except my background Image, although if I'm loading it by any form of an ISS it works fine. I just want to know why! (my background works if I load an image from the internet but I have an issue if I want to load it from my local computer). Thank you!

.flex-row-1 {    background: url(/images/black.jpg);  }

<div class="flex-row-1">    <div class="your-box">      <h2>You:<span id="your-result">0</span></h2>    </div>    <div class="dealer-box">      <h2>Dealer:<span id="dealer-result">0</span></h2>    </div>  </div>

https://stackoverflow.com/questions/65745818/load-html-direct-by-browser-vs-load-with-iisvisual-studio-2019 January 16, 2021 at 10:06AM