on website, is loading image faster or css code? - html

Question

I have code below. It has several divs and css code. The image pic size is about 45kb,small size. So, I want to know, should I use img directly or use the code below. Which one has the faster speed when page loading. Appreciate.
div.smileyface {
width: 300px;
height: 300px;
position: relative;
border-radius: 150px;
-webkit-border-radius: 150px;
-moz-border-radius: 150px;
display: block;
background: #ffe632;
background: -webkit-gradient(linear, left top, left bottom, from(#fffe8d), to(#f6d23e));
background: -moz-linear-gradient(top, #fffe8d, #f6d23e);
box-shadow: inset 0px -14px 14px rgba(0, 0, 0, .3), 0px 2px 20px rgba(0, 0, 0, .6);
-webkit-box-shadow: inset 0px -14px 14px rgba(0, 0, 0, .3), 0px 2px 20px rgba(0, 0, 0, .6);
-moz-box-shadow: inset 0px -14px 14px rgba(0, 0, 0, .3), 0px 2px 20px rgba(0, 0, 0, .6);
}
p.eyes {
width: 50px;
height: 80px;
background: #222;
border-radius: 100px/160px;
-webkit-border-radius: 100px 160px;
-moz-border-radius: 100px/160px;
position: absolute;
top: 40px;
box-shadow: 0 2px 0 rgba(255,255,255, 0.8);
-webkit-box-shadow: 0 2px 0 rgba(255,255,255, 0.8);
-moz-box-shadow: 0 2px 0 rgba(255,255,255, 0.8);
}
p.eyes.lefteye {
left: 75px;
}
p.eyes.righteye {
right: 75px;
}
div.smile {
width: 200px;
height: 70px;
border: 10px solid #222;
border-top: 0;
background: rgba(0,0,0,0);
-moz-border-radius: 0 0 120px 120px / 0 0 90px 90px;
-webkit-border-radius: 0 0 120px 120px 0 0 90px 90px;
border-radius: 0 0 120px 120px / 0 0 90px 90px;
position: absolute;
bottom: 50px;
left: 38px;
box-shadow: 0 2px 0 rgba(255,255,255, 0.8);
-webkit-box-shadow: 0 2px 0 rgba(255,255,255, 0.8);
-moz-box-shadow: 0 2px 0 rgba(255,255,255, 0.8);
}
div.corner {
width: 10px;
height: 30px;
background: #222;
border-radius: 100px/160px;
-webkit-border-radius: 100px 160px;
-moz-border-radius: 100px/160px;
position: absolute;
top: -12px;
-webkit-transform: rotate(65deg);
-moz-transform: rotate(65deg);
left: -12px;
}
div.corner.right {
left: 202px;
-webkit-transform: rotate(-65deg);
-moz-transform: rotate(-65deg);
}
<div class="smileyface">
<p class="eyes lefteye"></p>
<p class="eyes righteye"></p>
<div class="smile">
<div class="corner"></div>
<div class="corner right"></div>
</div>
</div>

Answer 1

According to YSlow, it is a best practice to Minimize HTTP Requests: use CSS sprites, avoid CSS images, combine files etc.
The overall goal should in the end be to optimize page weight, though.
Since the image is 45KB in this case, I would recommend the CSS solution - it is 2148 chars, which is 2KB. If all CSS is in one file, the CSS solution will save you 43KB and 1 HTTP request.
The CSS Solution might get even smaller with a tool such as FormatCSS and by minification.
45KB sounds like a very big file, unnecessary big even. Optimize Images could also be considered.

Answer 2

Here is a detailed explanation of what to use when. Hope it helps:
When to use IMG vs. CSS background-image?