在将新图像加载到网站时显示加载...动画

I have a website which will display an image statically, I have some image thumbnails below to that Preview section and when I click on the thumbnails, the big image will be displayed on the preview section, Im using jQuery here to replace the SRC of the IMG tag while click on thumbnails, so it takes some time to display the selected image on the browser, until the new image loads it is displaying the previous one there even after few seconds of click action on thumbs(Loading time into browser depends on internet connection), so I would like to display an Image saying "Loading.." while it loads into browser. Any help would be appreciated. I tried with onload() for img tag, but seems it is on first time load, since im just changing the SRC value alone its not working though. Here is my code looks likeI have a website which will display an image st