I need to make a button on top of the image that will open a specific form, how to organize it?

Question

css

The image should have a button indents from all edges as a percentage, when you hover over it, the gray lines turn into white, the background is transparent, the text is in the middle

Answer 1

Что-то вроде 
<div class="wrap">
       <img src="link">
       <div class="button"><button>Узнать больше</button></div>
</div>

.wrap {position:relative}
.button{position:absolute:top:50%; left:0;rigt:0; margin-top: - (half the height of the button); margin: auto;}