Let’s say that you have a large image (or several large images) on a particular page, and you want to let visitors know that the image is loading. You could use a piece of javascript to embed a “loading” image for all images that have not yet loaded, but unless you are loading a ton of very large images on a single page, we have a much simpler (and cleaner) method to accomplish the same thing.

Step 1: Find a preload image.

There are many fantastic sites out there that will allow you to create your own preload images. Our favorite is here. Just remember not to choose an icon that is too large (file size), or it may not load until after the larger image has loaded. Here is the one that we have created:

Step 2: Create the CSS

There is just a little bit of code to create here, and it can be pasted directly into your stylesheet. Just be sure to replace the “youricon.gif” text with your image name.

Code to paste into your stylesheet:
.load{background:url('images/youricon.gif') no-repeat center;}

Step 3: Applying the code
There are a couple of ways to do this, but this is probably the best solution (depending on your application). Simply encase the image you are interested in loading within a “load” div, and apply the width and height of your image to the div.

Example:
<div class="load" style="width:200px;height:200px">
<img src="large.jpg" alt="alternate text" /></div>

Here it is applied to an image:
You will likely need to clear your cache and reload this page to see the loading icon appear. A more thorough example of this loading icon in action can be found here.

As mentioned by contributor Lim Chee Aun below, you could also bypass the div and apply the .load class directly to the image itself, and here’s how you can do it:
<img src="large.jpg" alt="alternate text" class="load" style="width:200px;height:200px" /></div>The reason we hadn’t mentioned this idea initially, is if the image does not load it can break the look of the design. If you are absolutely positive you will not have any loading issues, you don’t care if the image needs to be centered (while validating xhtml strict), or if you are applying the class to multiple images, this may be a cleaner solution for you. See our updated example page below for examples of the method created both ways.

If this solution doesn’t fix the problem for you application, let us know what you are doing differently and we’ll be happy to go into more detail.

Compatibility:
This method has been tested in and is compatible with Internet Explorer 5.5, 6, 7, Firefox (PC and Mac), Netscape and Safari (PC and Mac).

That’s all folks!

If you have an idea or article that you would like to contribute, send it on! We’re always looking for good, quality articles. Note that we will not republish an article that has been published elsewhere, so keep it original!

Now excuse me for pulling up an old chestnut, but this is one that comes up often for people who are just starting out with CSS and want to avoid the extensive javascript output by many website design applications such as Dreamweaver and the dreaded Front Page. This method only requires a very minor understanding of CSS, cleans up your markup and achieves the desired effect.

Step 1: Creating the CSS.

First, let’s start with the CSS we’ll need. This step is very simple, as there is only one line that you will need to add to your stylesheet. Decide what name you would like to use for your preload. In this case we have gone with the creative Class name “preload.” If this is fine for you, simply paste this code into your stylesheet. Otherwise, change the Class to another name you are more comfortable with, bearing in mind you will need to do this on the final code as well. I’ll cover why we chose to use a Class instead of an ID in just a minute.

Code to paste into your stylesheet:
.preload{display:none;}

Step 2: Creating the DIV.

Next, we’ll create the actual DIV that will contain the images you want to preload. If you are using a site that you created yourself, this can go in the footer area of your page, as this will ensure that the main portion of the site loads before your preloaded images. If you want this preload active on every page of your site, make sure to either A. Copy the code to each page of your site, or B. (Preferred) include a footer.txt file that will contain this preload on every page of your site. That way, if you need to add or remove an item, you can do it in one place instead of on every page. If you are using a site that has a WYSIWYG editor and you only want the preload on one page (or want to add different images for preload on each page), you can do this by clicking on the “view code” or “view source” button in the editor and entering the code at the bottom of the editor. The reason we chose to use a Class rather than an ID is because this will grant you the most flexibility to add more than one set of preloads to a site. Say you have a web site with database-driven content. You have a set of preload images in the footer that is outputted automatically on every page, but one particular page also needs a few more preloaded images. You can accomplish this simply by adding those few images into the WYSIWYG editor as described above, without having to worry about having two DIV’s with the same ID on a particular page.

Code to modify/paste into your web site:
<div class="preload">
<img src="images/dog-over.gif" alt="Dog" />
<img src="images/cat-over.gif" alt="Cat" />
<img src="images/mouse-over.gif" alt="Mouse" />
</div>Remember to add an alternate tag to each image!

Step 3: Testing.
Try it out! For our example, we created two different sets of images. One has a CSS preload, while one does not. Run your mouse over each, see the difference? The preloaded image loads immediately, while the non-preloaded image flashes before loading. Note that once you have moused over the non-preload image once, you will need to refresh the page to see it flash again.

WITH Preload

Compatibility:
This method has been tested in and is compatible with Internet Explorer 5.5, 6, 7, Firefox (PC, Linux and Mac), Netscape and Safari (PC and Mac).

That’s all folks!

If you have an idea or article that you would like to contribute, send it on! We’re always looking for good, quality articles. Note that we will not republish an article that has been published elsewhere, so keep it original!