How to center images for small mobile that were floated on desktop - image

Question

I often float images either left or right around text on desktop but I want them centered for small mobile devices and the paragraph to drop below the image using Responsive design. I've got the paragraph dropping below the image using an online mobile viewing device but not when I try to view it via my computer. The image won't center online or on my computer.
Here is what I have found after many hours of research:
I have this set up for all images:
img{
border:0;
max-width:100%;
height:auto;
}
I have this set up for all paragraphs: it pushes the paragraph down below a floated image when the width of the paragraph is less than 10em (about 200 px).
p:before{
content: "";
width: 10em;
display: block;
overflow: hidden;
}
I have applied the following for images to media queries less than 320 and max of 480:
img{
max-width:100%;
display:block!important;
margin:0 auto !important;
float:none !important;
}
(i had to add !important to some of them or they wouldn't take but it's still not accepting margin: 0 auto; )
Can anyone see what I'm doing wrong?

Answer 1

Here you have a working update of what you need: http://jsfiddle.net/ancpjmet/3/
I changed min-devide-width to min-width and max-devide-width to max-width to be able to see the changes on my desktop browser in Google Chrome.
You have to set the div wrapping the img to float: none;, not the img:
#media only screen and (min-width:320px) and (max-width:480px) {
#image-wrapper{
float: none !important;
}
#image-wrapper img{
max-width: 80%;
display: block;
margin: 0 auto;
}
}
I also rebuild your .clearfix class to be more consistant and work in all browsers:
.clearfix:before,
.clearfix:after {
content: '\0020';
display: block;
overflow: hidden;
visibility: hidden;
width: 0;
height: 0; }
.clearfix:after {
clear: both; }
.clearfix {
zoom: 1; }
Take a look at the changes in the jsfiddle given.