How to Optimize Images for Search Engine Optimization

Website publishers who optimize images for search engine optimization will find rewards from site visitors and search engines alike.

It is not enough that Internet access speeds are faster than ever. Even Google has found that a difference of as little as 300 milliseconds affects user perceptions of website speed.

The two biggest culprits are scripts, such as javascript, and images. Both are a matter of size and number. Publishers can reduce the number of javascripts, but they will find a challenge in trying to reduce their file size.

Not so with images. They can easily reduce their file size and how fast they load, which in turn is a benefit to users and a positive for search engines.

Step 1: Reduce Dimensions

The easiest and quickest way to optimize images for SEO is by limiting the dimensions of the image. An image that is 500 x 400 is 200,000 pixels.

If that same image is only 10 percent narrower or 450 x 360, the total pixels is 162,000 or 19 percent smaller. The user perception between the larger and smaller image is a 10 percent difference, but the speed impact is a 19 percent difference.

Step 2: Reduce Quality

Reducing quality sounds bad at first blush, but computer monitors can show fewer pixels than what appears in a high quality photo.

Use the quality settings in Gimp, Photoshop or other sophisticated image software to reduce the number of pixels in an image. For example, a test for this article reduced one image from a whopping 1.7 megabytes down to 55 kilobytes. A plugin such as RIOT reduced another image from 45 kilobytes to 12 kilobytes.

At some point, reducing quality too much can make an image look muddy. So an element of common sense must prevail.

Step 3: Reduce the Number of Images

The third step also is an easy one, although it also requires good judgment and common sense.

Some website pages clearly suffer from having too many images. It’s a good idea to have a rule of thumb about the number of images on a page based on the length of the article. For example, try having one image for every 200 to 300 words.