Changing WordPress Themes? Things You’ll Want to Do

James George

Sometimes when you’re running a WordPress site, you just want to freshen things up. Sometimes your site becomes stale and you get tired of looking at it. Other times, the design itself becomes outdated – so you decide it’s time to change your theme. This is nothing out of the ordinary, but can cause problems when you least expect it. In this article, I’ll cover some things you should do when changing WordPress themes.

Regenerate Thumbnails

Regenerate Thumbnails

Your theme, depending on where you got it, may have its own set of thumbnail sizes for the images it displays. These images could be in your posts or archives, or even search results. When you switch themes, it may not generate the image sizes it needs for these areas. It’ll try to take the existing images and stretch them to fit, distorting your images and ruining the look of your site. Lucky for you, there’s an easy fix, by the way of the plugin Regenerate Thumbnails, which does just that. Install it, run it, and it will regenerate all post thumbnails at the sizes needed for your posts.

Test All Functionality

More often than not, you’ll run into issues with plugins and themes. Sometimes certain themes and plugins don’t mix well together. This is usually due to conflicts with the PHP code between the two. Maybe they work against each other and your browser doesn’t know which one to display or override. The sky’s the limit, and it’s a common occurrence.

It’s a good idea to go through and test all of the features of your site. If you have plugins that add extra functionality to your site, you’ll want to make sure those features still work. If not, and they are essential to your site and its success, you’ll need to pick another theme, or code that capability into the new theme yourself. Plugins break often, because everyone codes things differently. It would be impossible to make every theme work with every plugin at all times.

Create a Child Theme

If you plan on making major changes to your theme, such as adding custom functions, or coding extra features into your site, you wouldn’t want a theme update to wipe them all out. Before you even get started with making changes to the new theme, create a child theme to handle all of the changes. Keeping the new code separate will make things easier much later, while avoiding possible disasters like losing your work.

Add in Custom Code

Custom Code

You can always add in custom functionality to your WordPress site via the functions.php file. However, the custom code I am referring to is tracking code for Google Analytics, custom advertising codes, and any other scripts you might be using. Those don’t translate from theme to theme usually. Many theme makers are making sections in the theme options area where you can copy and paste your codes. You’ll want to make sure to do that in your new theme.

I can’t tell you how many times I’ve switched themes for a site and forgot to add in that code or custom advertising code from affiliates. Don’t lose out on valuable stats or revenue!

Keep Your Old Theme Handy for a Few Days

I know your tendency. When you install your new WordPress theme, your initial thought is to delete the old one, but you might want to hang on to it, and I’ll tell you why. A lot of times, we think things are great, and then we’ll discover something wrong which causes a huge hiccup. If you delete your old theme, you have nothing to revert to in times of early trouble. I have learned the hard way to keep the old theme around for the first week, just to have something to revert to in order to keep things going while I handle the issues with the new theme.

You never want to leave yourself in the situation where you’re live and your site is broken. You’ll lose visitors, you can lose revenue, and you end up putting pressure on yourself to make a hurried solution to the problem. Don’t do that to yourself. Be sure to have a fallback method.

BackUp Your Entire Site

WordPress Backup

Make a backup of your entire site, just in case something major goes wrong. If you pick up a bad theme, you could end up messing everything up. Sometimes hackers will insert malicious code into free themes just to cause destruction and trouble. Don’t be a victim! Backup your entire site, including your database, so that you can restore everything if something major goes wrong. Most hosting companies have a backup utility you can use to backup your site for free. It’s something you should be doing regularly anyway.

Test It on Different Devices

I know most themes are responsive now, but sometimes a theme just isn’t crafted well for a good mobile experience. Try it out on a tablet and a smart phone. Make sure that the tap areas are large enough and are far enough apart from each other. Play with it, and try to break it. More than 80% of people browsing the web are doing it on a tablet or smartphone now. Make sure it looks great and works properly for them.

Check Posts and Pages for Shortcodes

This is why shortcodes are both good and bad. If your old theme formatted text or added functionality via a shortcode, it most likely won’t be there now. If you added these shortcodes to posts and pages throughout your site, they won’t be there now. Visitors will just see gibberish code. That’s ugly, and people will think your site is broken. Make sure to go through every post and page with shortcodes that are no longer available, and delete them.


A lot of people don’t think about these things when they switch to a different WordPress theme. That decision isn’t something to be taken lightly, because there can be a lot of work involved in it. You should choose your themes carefully, and should test your new theme vigorously to ensure that it holds up to your expectations. It’s your job to ensure that your visitors get the best experience possible.