実際の画像を点滅させずに正しい寸法を取得する方法:
(function( $ ){
$.fn.getDimensions=function(){
alert("First example:This works only for HTML code without CSS width/height definition.");
w=$(this, 'img')[0].width;
h=$(this, 'img')[0].height;
alert("This is a width/height on your monitor: " + $(this, 'img')[0].width+"/"+$(this, 'img')[0].height);
//This is bad practice - it shows on your monitor
$(this, 'img')[0].removeAttribute( "width" );
$(this, 'img')[0].removeAttribute( "height" );
alert("This is a bad effect of view after attributes removing, but we get right dimensions: "+ $(this, 'img')[0].width+"/"+$(this, 'img')[0].height);
//I'am going to repare it
$(this, 'img')[0].width=w;
$(this, 'img')[0].height=h;
//This is a good practice - it doesn't show on your monitor
ku=$(this, 'img').clone(); //We will work with a clone
ku.attr( "id","mnbv1lk87jhy0utrd" );//Markup clone for a final removing
ku[0].removeAttribute( "width" );
ku[0].removeAttribute( "height" );
//Now we still get 0
alert("There are still 0 before a clone appending to document: "+ $(ku)[0].width+"/"+$(ku)[0].height);
//Hide a clone
ku.css({"visibility" : "hidden",'position':'absolute','left':'-9999px'});
//A clone appending
$(document.body).append (ku[0]);
alert("We get right dimensions: "+ $(ku)[0].width+"/"+$(ku)[0].height);
//Remove a clone
$("#mnbv1lk87jhy0utrd").remove();
//But a next resolution is the best of all. It works in case of CSS definition of dimensions as well.
alert("But if you want to read real dimensions for image with CSS class definition outside of img element, you can't do it with a clone of image. Clone method is working with CSS dimensions, a clone has dimensions as well as in CSS class. That's why you have to work with a new img element.");
imgcopy=$('<img src="'+ $(this, 'img').attr('src') +'" />');//new object
imgcopy.attr( "id","mnbv1lk87jhy0aaa" );//Markup for a final removing
imgcopy.css({"visibility" : "hidden",'position':'absolute','left':'-9999px'});//hide copy
$(document.body).append (imgcopy);//append to document
alert("We get right dimensions: "+ imgcopy.width()+"/"+imgcopy.height());
$("#mnbv1lk87jhy0aaa").remove();
}
})( jQuery );
$(document).ready(function(){
$("img.toreaddimensions").click(function(){$(this).getDimensions();});
});
<img class = "toreaddimensions"で動作します...