I did the following
echo"<div class='carousel-item active' style='background-image: url('img/intro-carousel/". $row["img_pag_princ_car"] . "')>"
But you're returning the following:
<div class="carousel-item active" style="background-image: url(" img="" intro-carousel="" 01_gigaclima_indoor.jpg')="">
What am I doing wrong? Why are you replacing /
with ?