There are some simple steps to follow when writing SEO friendly alt text. Most importantly, you want to describe the image as accurately as possible. Could you envision what the image is if someone just read to you the description? At the same time, you want to keep it concise, with no more than 125 characters. Next, make sure to use appropriate keywords if possible, but don’t go stuffing as many keywords as possible into the alt text. Google will pick up on it eventually and it could cause you issues.