Often as a site grows, its performance degrades sharply. This can happen for many reasons, and is typical for a site that continually undergoes maintenance. As a project ages, the content often grows as well. More data, more code revisions, more ideas to turn into code for the site, etc.

I’m exploring this subject because a site of mine is in need of a performance boost. It was a snappy little site when I first launched it, but I’ve had many more ideas since then, and I’ve implemented almost all of them. Now regular browsing through the site is noticeable slower.

I’ve got a short list of performance enhancing ideas that I’m going to explore below.

Separating CSS and JS Files

For starters, if you have inline CSS or JS, you should separate these into separate files. This is a huge performance win, because a browser can cache mystyles.css or javastuff.js, but can’t cache it if it’s included inline in your page source code. Most performance wins happen client side – taking advantage of caching is often more efficient than making slight changes to server side code, though this isn’t a rule that’s set in stone; You could have terrible server side code that slows down the site too. My site in question already has the CSS and JS files separated, but it’s worth mentioning in case you haven’t done this.

Minifying CSS and JS Files

This is something that enterprise many sites do, so I thought I would go ahead and do this. Basically, it means removing spaces,tabs, and line returns wherever possible so that the file size is smaller, but the code executes as normal. When minifying a CSS file, I prefer to leave one CSS selector per line, and then listing each CSS property after it. This reduces file size, but makes the file still human readable/editable.

Here is an example of a fully minified CSS file from MSN – http://tk2.stc.s-msn.com/br/hp/11/en-us/css/hp_1.css – I think this is overdoing it, and doing it this way is probably done through an automated script, as this would be next to impossible for a developer to edit in a development environment.

For complex sites, this is going to be a better win than for simple sites. I saw about a 20% decrease in file size. For very, very simple sites (read very), using an external CSS file can slow things down because of the server disk access time of retrieving the external CSS file. The original Google page, for example, only has a few lines of CSS, and therefore uses inline CSS. For anything more complicated, include it in an external file.

Reducing Image Use

Many blogs and news oriented sites use too many images. This slows things down for first time readers, who don’t have the images cached. A good tool to examine load times of everything on your site is Firebug, a plugin for Firefox. You can get the latest version of Firebug here. The image below is a screen capture of one of the features in Firebug that lets you examine exactly how long everything took to load. If your site is nearing half a megabyte (~500kb), it’s time to put less on your pages, or use smaller images.

Using Less Database Queries

This is very important on some sites, and irrelevant on others. If you are using a basic installation of Wordpress, for example, there really aren’t too many ways for an average person to speed it up, without writing the developers and telling them to use less queries next release. For heavily customized sites based on existing platforms and fully custom database driven sites, database queries can be the make or break of your site performance. Basic rule: if you are writing your own queries, and you don’t know how they perform, then you shouldn’t be writing your own queries. Having said that, never outright trust queries from other somewhat experienced developers. Developing for my firm, a Fortune 500 company, we have often encountered popular plugins for Wordpress or modules for Drupal that have queries in them that are written poorly. Just because another developer made it, doesn’t mean they did it right.

Another way to use less queries, is to outright display less content. This is easy to accomplish if you’re using a blog platform. If you’ve got 20 posts a page, reduce this number. The number of queries your blog site makes is directly proportional to the number of posts or entries it is trying to display.

Better Hosting Plan or Better Hardware

This isn’t an option for me, because the next level of hosting plans with GoDaddy is out of my current budget range. For others, however, it may be an option. It’s worth looking into.

Creating blog posts is extremely easy in Wordpress, but adding simple thumbnails to your posts is not. I’m not talking about adding images within the post content, but adding them to your theme so they display in a standardized way in your blog loop, and on individual post pages.

The problem is that though Wordpress allows inserting images within posts, there is no way to “attach” these images to the post, so that theme designers can pull standardized images out for display. By making a few changes to your Wordpress configuration and your theme templates, and by using the Post Thumbnails plugin that I have written, you will be able to add thumbnails to your site in an intelligent way.

Wordpress Configuration

First step is to login to your Wordpress admin dashboard and navigate to the Settings -> Miscellaneous page. Here you will need to change:

- Uncheck the “Organize my uploads into month- and year-based folders.”

- Change the Wordpress thumbnail size to your desired size. This is important! Take careful thought when making this decision – you will break old post’s thumbnails if you chose to change this value later. I recommend 50×50 pixels.

Plugin Installation

Download the Post Thumbnail plugin using this link. Unzip it and place the file within your wp-content/plugins/ directory. Navigate to the Plugins menu within the Wordpress admin dashboard and activate this plugin.

You’re going to need a default post thumbnail to be used when no image is associated with a post. Upload an image that is the same size as the thumbnail size you chose above to the wp-admin/uploads folder, or the same folder you have chosen for uploads if you’re using a custom location. On most installations that folder would be wp-content/uploads/.

After you’ve uploaded the image, paste the name into the first line of code in the plugin PHP file:

define('DEFAULT_POST_THUMBNAIL', 'default_thumbnail_file.jpg');

Change the above default_thumbnail_file.jpg to whatever your image was called.

Plugin Usage

After the plugin has been activated, you will notice a new box titled Post Thumbnail on the Wordpress Write and Edit screens. To get a thumbnail attached to your post, upload an image using Wordpress’ default image uploading mechanism, which is a button next to the Add Media label near the top of those screens. This opens up a popup window for uploading images. Upload your image, but you don’t need to insert it into the post. Instead copy the file name (ex. myimage.jpg) and then click on the X to close the window.

Next, paste the file name into the Source Image input field in the Post Thumbnail box and click save. After saving, you will notice that an image name will be displayed in the Generated Thumbnail box. This is the thumbnail version of your source image, that Wordpress resized for you when you initially uploaded the image.

Adding the Thumbnail to Your Theme

Now that thumbnails are being attached to posts, we need to modify our theme to display them. It’s up to you to decide where you want to place them, but I would recommend adding the thumbnail to your template wherever you use the Wordpress loop. Below is a code snippet that inserts a thumbnail into the Default Wordpress theme’s index.php file, so thumbnails will show up on the main page of your site. Only one new line needs to be added.

<?php while (have_posts()) : the_post(); ?>
  <div class="post" id="post-<?php the_ID(); ?>">
    <h2>
    <!-- Begin New Code-->
    <div style="float:left; margin:5px;">
      <?php echo get_post_thumbnail(get_the_ID()); ?>
    </div>
    <!-- End New Code-->
    <a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to 
    <?php the_title_attribute(); ?>"><?php the_title(); ?></a></h2>
    <small>
      <?php the_time('F jS, Y') ?> <!-- by <?php the_author() ?> -->
    </small>
 
    <div class="entry">
      <?php the_content('Read the rest of this entry &raquo;'); ?>
    </div>
 
    <p class="postmetadata"><?php the_tags('Tags: ', ', ', '<br />'); ?> 
    Posted in <?php the_category(', ') ?> | 
    <?php edit_post_link('Edit', '', ' | '); ?>  
    <?php comments_popup_link('No Comments &#187;', 
    '1 Comment &#187;', '% Comments &#187;'); ?>
    </p>
  </div>
<?php endwhile; ?>

Here’s what my above post looked like with the above template code:

Other templates like single.php and archive.php in the Default theme have very similar code where you can also insert the thumbnail. Your theme may differ, but usage is very simple. Just call the following function in your template wherever you want to display the thumbnail:

<?php echo get_post_thumbnail(get_the_ID()); ?>