I have created a fiddle with a jQuery solution.It blurs hovered part of image .Hope it helps:
jQuery
$('.pic').mousemove(function(event){
event.preventDefault();
var upX=event.clientX;
var upY=event.clientY;
$('#blurr').css({'display':'block','top':''+(upY-15)+'px','left':''+(upX-15)+'px'});
});
CSS
.pic{
display:inline-block;
}
/*below CSS for the blurring div*/
#blurr{
position:absolute;
display:none;
width:30px;
height:30px;
background-color:rgb(240,240,240);
border-radius:50%;
-moz-border-radius:50%;
-webkit-border-radius:50%;
box-shadow:0px 0px 10px 10px white;
-moz-box-shadow:0px 0px 10px 10px white;
-webkit-box-shadow:0px 0px 10px 10px white;
opacity:0.8;
filter:alpha(opacity=80); /* For IE8 and earlier */
}
Update 28/Feb/2014
HTML
<div id="container">
<div class="blurPic"></div>
<img src="http://i.imgur.com/IGKVr8r.png" alt="follow picture" />
</div>
CSS
html,body{
margin:0px;
padding:0px;
}
#container{
position:relative;
}
.blurPic{
position:absolute;
top:0px;
left:0px;
width:0px;
height:0px;
box-shadow:0px 0px 0px 160px white inset;
-moz-box-shadow:0px 0px 0px 160px white inset;
-webkit-box-shadow:0px 0px 0px 160px white inset;
-ms-box-shadow:0px 0px 0px 160px white inset;
opacity:0.9;
filter:alpha(opacity=0.9); /* For IE8 and earlier */
}
jQuery
/**Give equal width and height as <img> to .blurPic**/
var hgt = $('.blurPic').width($('#container img').width());
$('.blurPic').height($('#container img').height());
/*****************************************************/
/*******Get shadow values*****/
var result = $('.blurPic').css('boxShadow').match(/(-?d+px)|(rgb(.+))/g)
var color = result[0],
y = result[1],
x = result[2],
blur = result[3];
/******************************/
/**Change box-shadow on mousemove over image**/
var blurStartW = hgt.width()/2;
var blurStartH = hgt.height()/2;
$('.blurPic').mousemove(function(event){
event.preventDefault();
var scrollLeftPos = $(window).scrollLeft(),
scrollTopPos = $(window).scrollTop(),
offsetLft = hgt.offset().left,
offsetTp = hgt.offset().top;
var upX=event.clientX;
var upY=event.clientY;
$(this).css({boxShadow : ''+(-offsetLft+upX-blurStartW+scrollLeftPos)+'px '+(-offsetTp+upY-blurStartH+scrollTopPos)+'px 20px 100px white inset'});
});
/*********************************************/
/***reset box-shadow on mouseout***/
$('.blurPic').mouseout(function(){
$(this).css({boxShadow : '0px 0px 0px 160px white inset'});
});
/**********************************/
Update 01/Mar/2014
The above fiddle uses Vague.js because CSS3 blurring may not work in all browsers
HTML
<div id="container">
<img src="http://i.imgur.com/IGKVr8r.png" alt="follow picture" />
<div class="revealPic"></div>
</div>
CSS
html,body{
margin:0px;
padding:0px;
}
#container{
position:relative;
margin-left:100px;
display:inline-block;
}
.revealPic{
position:absolute;
top:0px;
left:0px;
background-image:url('http://i.imgur.com/IGKVr8r.png');
background-color:white;
background-position:0px 0px;
background-repeat:no-repeat;
width:50px;
height:50px;
/*making div circular*/
border-radius:50%;
-moz-border-radius:50%;
-webkit-border-radius:50%;
-ms-border-radius:50%;
-khtml-border-radius: 50%;
}
jQuery
var hgt = $('#container'),
bgt = $('#container .revealPic');
var bgtHalfW = bgt.width()/2,
bgtHalfH = bgt.height()/2;
/**Change position of .revealPic and background-image within it on mousemove over container**/
hgt.mousemove(function(event){
event.preventDefault();
bgt.show();
var scrollLeftPos = $(window).scrollLeft(),
scrollTopPos = $(window).scrollTop(),
offsetLft = hgt.offset().left,
offsetTp = hgt.offset().top;
var upX=event.clientX;
var upY=event.clientY;
bgt.css({backgroundPosition : ''+(offsetLft-upX+bgtHalfW-scrollLeftPos)+'px '+(offsetTp-upY+bgtHalfH-scrollTopPos)+'px',top:''+(-offsetTp+upY-bgtHalfH+scrollTopPos)+'px',left:''+(-offsetLft+upX-bgtHalfW+scrollLeftPos)+'px'});
});
/*********************************************/
/*Hide .revealPic div on mouseout*/
hgt.mouseout(function(){
bgt.hide();
});
/*********************************/
/*Using vague.js to make blurred image*/
var vague = $("#container img").Vague({intensity:10});
vague.blur();
/**************************************/
