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[WordPress] How to Serve Images from Subdomain

How to Serve Images from Subdomain

Hey there fellow bloggers! If you are serious about speeding up your blog, then you must have used tools like Pingdom and GTmetrix to test its speed. These tests usually show recommendations like serve images from subdomain, serve static content from a subdomain or from a cookieless domain or parallelize downloads across hostnames etc.

If you want to get rid of these flags in speed tests and want to speed up your blog, you should consider serving images from a subdomain. This is the easiest and completely free approach which helps in improving site load times.

In this article, I want to show you how to serve images from subdomain and improve page load time of your blog by reducing http requests from a single domain.

But, Why Serve Images From Subdomain?

Good question. In simple words, the number of connection a web-browser can make to a single domain is limited. Most modern browsers can make up to 6 connections per hostname at the same time.

Besides images, there are many things that loads from your domain. This includes scripts, CSS, JS, HTML, simple text files etc. A browser can’t load rest of the files from the same hostname until other files are loaded first. You can think of this as a queue.

This is why, you often read recommendations to use CDN services and other ways of improving site speed. Of course CDN services aren’t free. In such case, serving images from a subdomain is an effortless way of improving speed of your blog by some extent. This method can also be referred to as sharding.

Does Serving Images From A Subdomain Really Help?

Yes, it does. Images are one of the heaviest parts of any site. But they’re also one of the most crucial ones. For better SEO and to provide better understanding of your content, images are must-have.

A subdomain is considered as a separate website. By serving images from subdomain, it will take less time for a browser to load content from your server because the browser can simultaneously load content from different domains.

This significantly reduces the time a browser has to wait before it can serve all the content from your domain, dramatically improving load time of your blog.

I’m also serving images from a subdomain and you can checkout my blog’s speed ranking on Pingdom or GTmetrix before you continue.

If you are ready to learn how to serve images from subdomain, then keep reading.

Requirements

  • Some knowledge of cPanel and phpMyAdmin.
  • Patience, a lot of patience.
  • Ability to keep calm if things don’t go out as intended.

Services Demonstrated in This Article

Note: Replace http:// with https:// everywhere in this guide if your blog has https certificate (like mine).

How to Serve Images from Subdomain?

Step 1: Creating A New Subdomain

To begin with, we will need a subdomain. To create a subdomain, log in to your cPanel and find Subdomains option. Click it to enter.

Creating Subdomain on SiteGround

Under Create a Subdomain, enter the name of your subdomain. You can choose any name that makes sense. For example, you can use img, images, media or anything of your choice. I’m choosing media.

Choose your domain from the drop-down list (of you have more than one) on which you need to create this subdomain. I will choose techstuffer.com.

Change the Document Root to your WP Content folder. By default, it’s public_html/wp-content/uploads if you never changed it.

Creating Subdomain in cPanel

Attention: If you changed the upload path in past for any reason, enter that path here. For example, you could have changed the wp-content/uploads folder to content/files. In this case, enter public_html/content/files under Document Root.

If you’re unsure whether you changed this path or kept default, then open an image from your blog and see the path. If it looks like yourblog.com/wp-content/uploads/image.jpg, then you have the default path.

Now click Create and a subdomain will be created.

You now have a working subdomain. Great! So lets move ahead and tell WordPress to upload new images in the new location. Keep cPanel open. We will be coming back here.

Step 2: Changing Media Upload Path in WordPress

Log in to your WordPress dashboard and go to Settings > Media.

Under Full URL path to files, enter your complete subdomain including http://. I will enter https://media.techstuffer.com. Remember NOT to add any trailing slash (/) here.

Change Media Upload Path in WordPress

Save the settings.

If you can’t find the Full URL path to files option under Media settings, you can do this by entering a hidden WordPress options area. Enter your blog’s address in the following manner to access the options panel: http://yourblog.com/wp-admin/options.php.

Once the options area is open, search for upload_url_path. Enter the subdomain here including http:// and without a slash at the end. I can enter https://media.techstuffer.com here.

Change Media Upload Path in WordPress

Scroll down and save these changes.

Okay, so from now on, any new image uploaded to your blog will carry the new URL. If you upload image2.jpg, it will be available at http://subdomain.yourblog.com/image2.jpg.

You’ve told WordPress about the new media upload path. Very well done. Now the next step is to change URLs of images in old blog posts to new ones. Keep reading on next page.

About the author

Parvez Shaikh

A blogger by profession, Parvez is passionate about new technology and gadgets. He's pro-encryption and enjoys his privacy. When not blogging, he enjoys reading books and other blogs or planning a never ending vacation.

8 Comments

  • Thank you for a great tutorial. I have do it and worked perfectly but not completely I still get the Parallelize downloads across hostnames Warning
    This I know is due to a directory of thumbnails for my Online Arcade Games Site that are not inside the uploads folder.
    How would I include these
    http://www.3aliens.org/wp-content/thumbs/fog/A/asteroid-mining-empire.jpg
    http://www.3aliens.org/wp-content/thumbs/mochi/A/abe-clone-wars_img1.jpg
    there’s a lot more of them

    • Hi Mitch. I’m glad to know this tutorial worked for you.
      About the ‘thumbs’. How exactly these thumbs are generated? By the theme you use? Or by a plugin?

      • Generated by a plugin but these are from an old setup the current thumbs are put into the uploads directory.
        I have found a solution to move them into the uploads directory and change the posts image urls a lot of work so I will leave that for when I have free time.
        thanks for getting back to me.

  • For this, and my mistake if I missed it in the tutorial itself, but would the existing uploads directory have to be moved into the new sub domain so that past images work normally? Thanks.

    • I’m sorry for replying late and I hope you’ve found your answer already.
      You are not actually creating a new directory. You are keeping images in the same directory (wp-content/uploads) and just changing the domain to a sub-domain. So you will not need to move images anywhere.
      Just follow Step 3 and 4 so images are served from new location.

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