image optimization is very crucial because it can bring you a lot of traffic to your website. Image SEO is an targeted and organic way too. If you are missing image optimization you will miss so much traffic. Here are some tips to optimize images for search engines.
ALT text is the only thing that search engines spider can read. Alt text is the important thing in image optimization. It is a simple text to describe about that image. It should be descriptive and informative. Don’t use more lengthy or short alt tags. You can also use title tag in images. But it cannot boost performance. Title tag is only for humans, to read it.
Using unreadable file names are one of the mistake. It is just like permalink to the pages. Instead of using numbers and unreadable names, you should use your targeting keywords as image name. Hence search engines can identify that image well.
Reduce File size & Optimize image
Optimized images can improve performance. It can load much faster. You should reduce the file size without losing its quality. Here are some tools to optimize your images:
Yahoo Smush.it (Online)
Your content should be related to that image. If your content doesn’t match with the image, search engines will consider it as spam and did not rank well.
Link that image
Search engines like links. This is a plus point and this is not a essential thing. If you linked images to any pages or that images itself you may get better result.
Submit Image SiteMap
Image sitemap will helps to crawl images much better, that search engines are missing. Your images will get indexed on image search. Keep your images in separate XML sitemap, not in your sitemap that contains pages. Here is the sample code for an image sitemap from Google Webmaster tools.