对于不希望更改原始位置或图像的函数。

$(this).clone().removeAttr("width").attr("width");
$(this).clone().removeAttr("height").attr("height);

我已经做了一些变通的实用函数，使用imagesLoaded jquery插件: https://github.com/desandro/imagesloaded

            function waitForImageSize(src, func, ctx){
                if(!ctx)ctx = window;
                var img = new Image();
                img.src = src;
                $(img).imagesLoaded($.proxy(function(){
                    var w = this.img.innerWidth||this.img.naturalWidth;
                    var h = this.img.innerHeight||this.img.naturalHeight;
                    this.func.call(this.ctx, w, h, this.img);
                },{img: img, func: func, ctx: ctx}));
            },

你可以通过传递url，函数和它的上下文来使用它。函数在图像加载后执行，并返回创建的图像及其宽度和高度。

waitForImageSize("image.png", function(w,h){alert(w+","+h)},this)

My situation is probably a little different. I am dynamically changing the src of an image via javascript and needed to ensure that the new image is sized proportionally to fit a fixed container (in a photo gallery). I initially just removed the width and height attributes of the image after it is loaded (via the image's load event) and reset these after calculating the preferred dimensions. However, that does not work in Safari and possibly IE (I have not tested it in IE thoroughly, but the image doesn't even show, so...).

Safari保留了前一张图片的尺寸所以尺寸总是在后面一张图片上。我认为这和缓存有关。因此，最简单的解决方案是克隆图像并将其添加到DOM中(重要的是将其添加到DOM中以获得with和height)。给图像一个可见值为hidden(不要使用display none，因为它不起作用)。获得尺寸后，删除克隆。

下面是我使用jQuery的代码:

// Hack for Safari and others
// clone the image and add it to the DOM
// to get the actual width and height
// of the newly loaded image

var cloned, 
    o_width, 
    o_height, 
    src = 'my_image.jpg', 
    img = [some existing image object];

$(img)
.load(function()
{
    $(this).removeAttr('height').removeAttr('width');
    cloned = $(this).clone().css({visibility:'hidden'});
    $('body').append(cloned);
    o_width = cloned.get(0).width; // I prefer to use native javascript for this
    o_height = cloned.get(0).height; // I prefer to use native javascript for this
    cloned.remove();
    $(this).attr({width:o_width, height:o_height});
})
.attr(src:src);

这个解决方案在任何情况下都有效。

$("#myImg").one("load",function(){
  //do something, like getting image width/height
}).each(function(){
  if(this.complete) $(this).trigger("load");
});

来自克里斯的评论:http://api.jquery.com/load-event/

我使用不同的方法，简单地使Ajax调用服务器，以获得图像对象在使用时的图像大小。

//make json call to server to get image size
$.getJSON("http://server/getimagesize.php",
{"src":url},
SetImageWidth
);

//callback function
function SetImageWidth(data) {

    var wrap = $("div#image_gallery #image_wrap");

    //remove height
     wrap.find("img").removeAttr('height');
    //remove height
     wrap.find("img").removeAttr('width');

    //set image width
    if (data.width > 635) {
        wrap.find("img").width(635);
    }
    else {
         wrap.find("img").width(data.width);
    }
}

当然还有服务器端代码:

<?php

$image_width = 0;
$image_height = 0;

if (isset ($_REQUEST['src']) && is_file($_SERVER['DOCUMENT_ROOT'] . $_REQUEST['src'])) {

    $imageinfo = getimagesize($_SERVER['DOCUMENT_ROOT'].$_REQUEST['src']);
    if ($imageinfo) {
       $image_width=  $imageinfo[0];
       $image_height= $imageinfo[1];
    }
}

$arr = array ('width'=>$image_width,'height'=>$image_height);

echo json_encode($arr);

?>

这对缓存的和动态加载的图像都有效。

function LoadImage(imgSrc, callback){
  var image = new Image();
  image.src = imgSrc;
  if (image.complete) {
    callback(image);
    image.onload=function(){};
  } else {
    image.onload = function() {
      callback(image);
      // clear onLoad, IE behaves erratically with animated gifs otherwise
      image.onload=function(){};
    }
    image.onerror = function() {
        alert("Could not load image.");
    }
  }
}

使用此脚本:

function AlertImageSize(image) {
  alert("Image size: " + image.width + "x" + image.height);
}
LoadImage("http://example.org/image.png", AlertImageSize);

演示:http://jsfiddle.net/9543z/2/