The problem is that a span has no size by itself. It grows to its content's size. In your example, there is no content so the span will be of 0px width.
Here's a display of the problem, using just background color but the same is valid for images. I put two divs, one red and one blue, we can only see the blue one since it has text in it.

<span style="background:red;"></span>

<span style="background:lightblue;">Test</span>

If you do not want to put text inside, you'll have to give it a width and a height. But since a span is meant to display inline, you'll need to change that too with display:inline-block or display:block

带文本的span它显示背景图像

<a href="#"> 
     <span style="background-image: url('https://picsum.photos/300/200.jpg')">LOREMLOREM</span>
     <span class='Title'>Gradjevinski radovi</span>
</a>

span无文本它不显示任何内容，因为span本身没有大小

<a href="#"> 
   <span style="background-image: url('https://picsum.photos/300/200.jpg')"></span>
   <span class='Title'>Gradjevinski radovi</span>
</a>

因此，请使用background-image在span中添加一些文本