However, if you use a CDN to host your images, they may not get included in the general sitemap generated for your website, since such common sitemaps usually include only files belonging to the same domain. So consider creating a separate image sitemap for such cases.
Most WordPress SEO plugins such as RankMath or Yoast create a sitemap that includes images along with posts and pages (in the same sitemap) by default. You can also choose to exclude or include featured images since those tend to be ‘fancy’ at times and may not necessarily add value if indexed.
2. Use a CDN
Use an Image Content Delivery Network to help you load images much faster. Delivering high-quality images can slow down your website terribly – which is never good for SEO of course.
If you aren’t sure what an Image CDN is, or a CDN too, here’s a really quick explanation –
What is a CDN?
CDN is an acronym for Content Delivery Network. It is quite literally that.
A CDN is a network of connected servers all over the world in different data centers.
When a user visits your website, the data center that is physically closest to that visitor’s location serves up your content. Which obviously makes it faster.
For example, let’s say your website’s content sits on a server on the West Coast. A visitor from the East Coast lands on your website and browses through your site.
Now, fetching content from the West Coast all the way to the East will take time and slow down your website. Instead, if you use a CDN, your content could be sitting in a Data Center in New York, making it that much faster to load your website.
Google takes website speed quite seriously and so should you. Using a CDN can help improve your website’s performance dramatically.
Of course, there’s more to it than that really simplified explanation. If you are hungry for more about CDNs, read our detailed CDN guide. Read this for a list of the best free CDN solutions.
What is an Image CDN?
An image CDN is very similar to a regular CDN that I just described – but it has the added ability to transform an image, modifying its size, format, and quality, so that the image is optimized for the device that it is being viewed on.
Here are some popular providers for Image CDN services –
Optimole – Compresses, transforms, stores, and delivers images in an optimized manner. Optimole can integrate with your WordPress website easily using its WordPress plugin which has a stellar rating on WordPress.org. Read our detailed Optimole review here for more.
Quicq – Promises to speed up your image delivery performance. Read our detailed Quicq review here.
Lazy loading is exactly what it sounds like – images are loaded just in time on the visitor’s browser, when the visitor actually scrolls down or navigates to that area and “demands” that image.
How do you enable lazy loading?
Lazy loading for all images uploaded to the Media Library was added as a default feature in WordPress Version 5.5 (by adding a loading=”lazy” attribute to img tags that have width and height attributes). Later, WordPress Version 5.7 went on to include lazy loading for iframe tags as well.
Disable WordPress’s default lazy loading behavior or
Enhance WordPress’s lazy loading features by supporting lazy loading for
images outside the media library
browsers that may not support this WordPress attribute
Iframes or videos that WordPress is unable to lazy load
4. Enable Browser Caching
Browser Caching is when a browser saves downloaded resources locally and then serves those up from there instead of downloading them again when the user re-visits the website.
How to enable browser caching?
If you are not keen on dabbling with code, it is best to leave it to a caching plugin like WP Rocket or W3 Total Cache. If you are not afraid of coding, then follow these instructions to DIY your browser cache.
Repeatable Action Items for Each Image
Here’s a list of 6 action items that should be part of your content checklist. Make sure each of these image optimization requirements is adhered to before publishing any post with images.
5. Choose the Correct Image Format
“WebP lossless images are 26% smaller in size compared to PNGs. WebP lossy images are 25-34% smaller than comparable JPEG images”
Google notes on WebP
Google supports images in a number of formats, however, the relatively new and lesser-known format WebP is ideal. JPGs are usually used for photos. PNGs are typically used for illustrations and logos (because PNGs allow transparent backgrounds).
You should ensure that your image (and the alt text) is in line with the text content before and after the image. If not, it can get confusing and be misinterpreted by search engines too.
For example, it is unnatural to embed an image of, say, a spaceship between two paragraphs that describe a pasta recipe.
To summarize, all you need to do is deliver your images efficiently, help Google find your images, and understand your images accurately.
There’s so much SEO juice that these simple image optimization techniques can help generate. You have no excuse to ignore these really. Paying just a little attention to image SEO can help improve your website’s user experience dramatically. And the organic traffic that it generates is a welcome bonus.
Do leave a comment and tell us how you have been optimizing images for your WordPress website. Any image optimization WordPress plugin that you have tried and loved (or hated)?