我们如何在不眨眼的情况下获得正确的真实尺寸:

(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"…

另一个建议是使用imagesLoaded插件。

$("img").imagesLoaded(function(){
alert( $(this).width() );
alert( $(this).height() );
});

您可以使用HTML图像元素的naturalWidth和naturalHeight属性。(这里有更多信息)。

你可以这样使用它:

//you need a reference to the DOM element, not a jQuery object. It would be better if you can use document.getElementByTagsName or ID or any other native method
var pic = $("img")[0];
var pic_real_width = pic.naturalWidth;
var pic_real_height = pic.naturalHeight;

这似乎适用于所有浏览器，除了IE版本8及以下。

根本问题是WebKit浏览器(Safari和Chrome)并行加载JavaScript和CSS信息。因此，JavaScript可能在计算CSS的样式效果之前执行，返回错误的答案。在jQuery中，我发现解决方案是等到文档。readyState == 'complete'，例如，

jQuery(document).ready(function(){
  if (jQuery.browser.safari && document.readyState != "complete"){
    //console.info('ready...');
    setTimeout( arguments.callee, 100 );
    return;
  } 
  ... (rest of function) 

至于宽度和高度……根据你正在做的事情，你可能需要offsetWidth和offsetHeight，其中包括边界和填充。

$(document).ready(function(){
                            var image = $("#fix_img");
                            var w = image.width();
                            var h = image.height();
                            var mr = 274/200;
                            var ir = w/h
                            if(ir > mr){
                                image.height(200);
                                image.width(200*ir);
                            } else{
                                image.width(274);
                                image.height(274/ir);
                            }
                        }); 

//此代码帮助显示200*274维度的图像

这适用于我(safari 3.2)，从窗口内发射。onload事件:

$(window).load(function() {
  var pic = $('img');

  pic.removeAttr("width"); 
  pic.removeAttr("height");

  alert( pic.width() );
  alert( pic.height() );
});