Contrary to popular belief, WordPress image sizes are more complicated. If you don’t pay enough attention to the requirements, your website may look sloppy or slow down your website’s loading time. 

So, to properly manage your website, it is crucial to fully understand how image sizes function in WordPress, what the default image sizes are, and how to define custom image sizes.

Knowing this information in advance will guarantee you have the proper kinds of photos in the correct sizes and places to make the most of your visual content strategy.

Additionally, these strategies will make your content more worthy of sharing, increasing its visibility and traffic. According to statistics, readers only remember 10% of the text they read after three days, but if you include eye-catching images in your content, that percentage rises to 65%.

In this guide, we will share with you all the things you need to know about WordPress Image sizes and what you can do to optimise them effectively for the benefit of your website. 

Ready? Let’s go!

What Are The Image Formats in WordPress?

Before talking about WordPress image sizes, it’s critical to understand formats. JPEG and PNG are the two most popular image formats used online.

JPEG is typically the chosen format due to its smaller file size and good quality for photographs and images with many colours. PNG, on the other hand, functions better with pictures that have fewer colours, including icon graphics and line drawings.

The quality of the image and the speed of your site will be impacted by the format you choose for your image.

How to Pick the Right Image Format?

The fundamental guideline for choosing the appropriate format is nice and straightforward. PNG for graphics and JPEG for photos. That’s it!

Save your image as a JPEG if it has a lot of colour, varied textures, and gradients. Save it as a PNG if it has text, a logo, or flat colours.

What happens if you choose the inappropriate format?

Not much to the naked eyes. You won’t be able to tell the difference between saving a photo as a PNG or a graphic as a JPEG. The use of compression is when issues start to appear.

Image Compression: What Is It and How Does It Work?

Every image you publish to your website needs to be compressed to lessen its size without sacrificing quality. If it isn’t, your website’s speed will suffer, impacting the user experience and driving away disgruntled visitors.

The user’s device must download images to be viewed when they visit your website. The longer it takes for an image file to download, the slower your entire website will load because of the higher file size.

To enhance user experience, image compression strikes a balance between file size and quality.

The quality won’t likely be that different if you compress the same image as a JPEG and PNG. If you look closely at the PNG, you might notice some graininess, but nothing that would make you decide not to use it. The JPEG will, however, be much lower in size than the PNG. So you choose the JPEG.

The quality is evident when the same graphic is compressed as a JPEG and PNG. Although the PNG will have a finer image, the JPEG will be lesser file size. This is so because graphics do not benefit from JPEG compression, although images do.

What Are the Default Image Sizes in WordPress?

With your original image file and the three sizes WordPress generates by default, we’re always looking at four possible image sizes when it comes to WordPress:

  • Thumbnail size (150px square)
  • Medium size (Max width and height of 300px)
  • Large size (Max width and height of 1024px)
  • Full size (full/original size of your image)

WordPress accomplishes this to save you from manually resizing photos and ensure the optimum image size is chosen for various areas on your website.

How to Choose the Ideal WordPress Featured Image Size?

For readers to stay engaged, WordPress featured photos are essential. The featured image gives a sneak peek of the content, much like the cover of a book.

Although they can be incorporated with pages and custom post types, they most frequently occur with WordPress posts. Additionally, it’s critical to pick the appropriate size because the featured image can end up being displayed by search engines and social media websites.

Although there are varying views on the matter, the optimum WordPress featured image size is around 1200 x 630 pixels. No matter how large the screen of your reader is, an image with these proportions should fit your site appropriately.

It’s also important to keep in mind that Google emphasises that your WordPress featured image size must be at least 1,200 pixels wide for your pages to qualify for the Google Discover feed (a fantastic source of additional traffic from Google).

How to Choose the Ideal WordPress Header Image Size?

Similar to featured images, header images can offer a glimpse into the tone and theme of the page to your users. Although they are less likely to be shared across social media feeds or search results pages, having the proper size is still crucial for your site’s speed and integrity.

Header images frequently depend on the layout of a site. Therefore, their dimensions might vary greatly. Since there is no “one size fits all” solution, it is best to consider your site’s responsiveness and design before choosing the size of your WordPress header image.

Therefore, theme developers advise WordPress header images to maintain a 16:9 ratio, such as:

  • 1920 × 1080 pixels
  • 1280 × 720 pixels
  • 1152 × 648 pixels

WordPress does not provide a default size for header images, similar to featured images. However, your theme might have a feature under the Appearance menu that allows you to change the header size.

Where Does WordPress Store Your Images?

WordPress stores your uploaded images in the Media Library as far as your Admin panel is concerned. You can see every image you’ve uploaded by clicking on Library while your mouse is above the Media option.

The media type (image, video, audio, etc.) and date can be used to sort them. But keep in mind that if you haven’t turned off this feature in the Settings, you won’t be able to sort the images by date.

You may locate your uploaded image using the search box on the right. Simply enter a word from the image’s title, caption, or description to find it.

How Are Images Processed in WordPress?

WordPress will create additional images with three default image sizes and store them separately after you upload an image to your media library. As a result, you will see four options while uploading an image: the thumbnail, medium, large, and full-size options. The full-size option is the original picture size you upload, while the first three choices are known as default WordPress image sizes.

Because different image location places will call for various image sizes, WordPress has created these options. Therefore, you don’t need to manually modify and resize your images if you wish to utilise the same images in other places with varying resolutions. WordPress will handle the rest, and only one image is required.

How to Optimise Your Images for WordPress?

Without mentioning image optimisation, no image-related guide is ever complete. Although we have covered image optimisation greatly, offering a few simple recommendations doesn’t harm.

After all, you’ll need to know how to optimise your images when you add custom image sizes to ensure they don’t hinder the functionality of your site or use up more server resources than necessary.

Here are a few simple pointers to get you started with image optimisation after all that.

Choose the Right File Type

Simply selecting the proper file type for your images will greatly reduce their size. Although many other image files exist, JPEG and PNG make up the majority.

When it comes to colourful visuals, JPEG clearly dominates. Additionally, JPEG files can be further compressed to lower their file size with hardly any quality loss (if you do it right). In contrast, PNG is typically a superior choice for graphics, text, most screenshots, and drawings.

Resize Your Images

The file size of your images can be decreased quickly and simply by resizing the images. As a general rule, ensure that all of your website’s images are only as big as they need to be.

It makes no sense to have a single image on your website with a width more than the 1200px maximum if the maximum width of your website is 1200px.

Remember that we’ve also stressed the value of not developing new custom image sizes unless necessary.

Utilise Lossy Compression

Applying lossy compression after you’ve already optimised your images using other techniques is a terrific strategy to reduce the file size further.

It entails eliminating some image data, the removal of which won’t significantly affect image quality but can significantly reduce file size.

Implement Lazy Loading

Using lazy loading enables you to give images on the pages of your website priority. Images load in sync with page scrolling by the visitor. It indicates that only the graphics at the very top of the page will load instantly, but the rest of the page won’t load until the user scrolls past the fold.


WordPress image sizes may seem unimportant, but they can actually be a problem. You may occasionally discover that the image you upload doesn’t fit the intended image size. You have two options for resolving this. You can add custom image sizes or modify the default WordPress image sizes. Before setting the new image size, remember that it is not a good idea to upload large, high-resolution images. Large images will occupy a lot of space and delay your website’s loading. You can utilise the tips we gave you above or look for professional assistance.

Fortunately, we handle everything. When it comes to web design, our team at Digital Rescue has more than 20 years of experience. We also have industry-leading SEO and digital strategy knowledge. The outcome is a stunning website created with lead generating in mind. We are trusted by the best. Contact us for enquiries.