If you notice that an abundance of images on your web-site slows it down, it’s high time to optimize them. This is crucial for both good ranking and SEO, so you should always take into account how images are optimized on your website. The recommendations given below are applicable for both WordPress and other websites.

1. Select Appropriate File Format

As you already know images are made in the form of files, and every file has its format. The most widespread formats that are considered to be SEO friendly are the following:

JPEG are ideal for images and photos that contain a lot of colors. This format allows for high-quality compression and lower file size. However, compression makes up for information loss. Thus, JPEG files are not suitable for pictures containing texts, solid colors or graphics.

PNG is suitable for almost all kinds of images except pictures, because some old devices may not display them correctly. This format was created as an alternative to GIF, and it provides better quality of compression than GIF. Besides, PNG supports transparency which makes it perfect for background purposes.

GIF works well with images that have small, fixed amount of colors (no more than 256 unique colors). This format provides excellent compression that is not as complex as, for instance, for JPEG files. This format is not suitable for images with gradient colors. The size of GIF files is small and handy. Besides, animated GIFs are quite popular (especially for short tutorials), so feel free to use them in your posts.

2. Select appropriate resolution and DPI for the images

When you have decided upon file formats that can be used without problems, you should think where and why images should be places. Various locations of websites may require images or higher or smaller resolutions and DPI (dots per inch). Usually users choose Photoshop, Paint or GIMP to make a suitable resolution. Here are some tips for this software:

When working in Photoshop, use DPI of about 72 pixels and always choose “Save for web” command (especially useful for PNG images). Alternatively, you can select the regular “Save as” command and specify settings of medium quality (works well foe JPEG images).

When you work with GIMP, you should read through the official documentation to learn how to create images for the Web.

If you will use an online image editor or some other offline software, consider the tips for DPI provided for Photoshop.

3. Name images correctly

It is recommended to include keywords or phrases for your content in the file name. Take them into consideration, because it really may influence SEO.

4. Image File Size

Now you have an image with a correct file name, format, DPI and resolution. But it may still be too big for your SEO purposes. Is there any chance to compress it more? And what is the point? The answer is simple: “The smaller image is, the faster it will be loaded on any device”. Here are some recommendation for those who want to compress images more:

Use two command-line programs for Windows and Linux to compress files of JPEG and PNG formats. This can be software called Jpegtran (for JPEG) and Optipng (for PNG);

Use online tools like Compressor.io or TinyPNG.

5. Use Other Server or CDN for Storing Your Images

If you upload images on some other server or have it cached on edge servers of CDN solution, you origin servers will experience fewer load providing better performance for users.

6. Use Captions, Alternate Text, Image Descriptions

Seems like the images are ready for being downloaded on your website. But before you finally insert them in your content, don’t forget to use the above texts, because they are very important for SEO benefits. Look for unique variants for every image and pay particular attention to alternate text. Use appropriate keywords and phrases that are both connected with your content on the page and images. Thanks to that you will get higher traffic from image searches, and search engines will rank your content better.

7. Extra options for WordPress Sites

If you website works on WordPress, you can use plugins and services:

Jetpack – a suite with free CDN service;

Simple Image Sizes helps to resize and customize WordPress image sizes;

YoastSEO – plugin that simplifies creation and adding of texts as described in the Tip#6;

WP Smush and ShortPixel  serve for additional compression of images prior to uploading them into WordPress media library;

Regenerate Thumbnails is used for what its name suggests - regenerating your WordPress thumbnails.

These tips for image optimization are not hard to follow, and they may give brilliant results for your SEO and website speed in the future.