Triangle in CSS inside a box [closed]

Answer 1

Creative use of borders to achieve this effect, no images were harmed in the following sample and you can even set the position of the arrow on the element itself - becomes more straightforward if you can hardcode it for your design.

HTML

<div class="top">
    <span class="arrow" style="left:40%"></span>
</div>

CSS

.top {
    background:url(http://blog.positscience.com/wp-content/uploads/2013/08/ice-cream3.jpg);
    background-size:cover;
    width:300px;
    height:300px;
    border:1px solid #888;
    position:relative;
    overflow:hidden;
}
.arrow {
    border:30px solid #aaa;
    border-bottom:none;
    border-color:transparent #aaa transparent #aaa;
    position:absolute;
    left:0;
    bottom:0;
}
.arrow:before, .arrow:after {
    content:'';
    position:absolute;
    width:5000px;
    bottom:0;
    height:30px;
    background:#aaa;
}
.arrow:before {
    right:30px;
}
.arrow:after {
    left:30px;
}

Working JSfiddle sample.

Or the full integrated sample here.