Image optimization is an important part of both SEO and UX. When browsing your page, users usually scan the content visually. Titles, images, and emphasized elements are the first things they will notice, so having a picture to enrich your content is worth investing your time into. However, not any image will do the job. They need to be optimized in a proper way, following certain SEO image optimization tips so they don’t do more harm than good. Badly optimized, or unoptimized images can increase the loading time of your page and leave you without inpatient visitors. They are impatient, especially these days, and the average human attention span is not what it used to be.

There are a couple of basic “a must do” rules that can help you with image optimization:

1. Relevance and naming
2. Choosing the format
3. Resize images
4. An appropriate caption
5. Alt text is a must
6. Image sitemaps

Relevance and naming

An appropriate image can and will leave an impression at your users. You need to choose images that are relevant to the content of a page so they can improve the impression it leaves at visitors. The best way would be to add original images, especially if you are selling a product. Adding a free stock image, in this case, is far from recommended. Also, naming your images in a detailed, descriptive, and unique way can improve your search engine ranking results. Crawlers can’t see your images but will read the names and attributes instead.

Choosing the format

There are a couple of formats widely spread today:

• JPEG
• GIF
• PNG
• SVG

At the moment the best format you can use in most cases will be jpeg. It is the best quality images you can get for small file size. PNG is used when you need to keep the background transparency, but are larger in size. SVG is mostly used for logos, icons, and in some cases for illustrations.

Resize images

To reduce the size of your output file you can scale down the image. There is no point to load large 2k pixels images only to display 200×200 pixels. So scale it down. A recommendation is to use different image sizes for different display sizes. It is possible with the <srcset> attribute. To reduce the size, even more, you can remove various metadata from images, and compress them.

Scaling the huge image is the best move if you need to display it as small.

An appropriate caption

A caption is a descriptive text that helps your visitors to understand, and to enhance, the visual representation of your image. The smart utilization of keywords with your caption helps your page for better listing in search results. The captions should always be in context with your content.

Alt text is a must

Alt text is shown when, for some reason, images are not displayed. They are also used for accessibility for physically impaired people. As for SEO, you should add alt attributes relevant to the picture and the content on your website and they will help you rank in the search engines. The best practice is to add alt to all images.

Image sitemaps

Image sitemap information helps crawlers discover images that may be hidden from them for a few particular reasons. So in order to let them index your images, you need to list their location in an image sitemap.

Image sitemap is like indexing images in your gallery and pointing to their location.

These are some of the SEO Image optimization tips you may need as a starting step toward the advanced SEO optimization.