When adding graphics or images to your web pages always place your main keyword and LSI keywords between the Alt"" speechmarks in the HTML source code. The search engine spiders cannot see an image, so they rely on whatever is written here to define what it is. Therefore, this helps a lot with your SEO. Cheerz, Ray
It is the general tips that most webmaster must know and need to do it each time they have picture in blog and want google to crawl it. But however, as Giamatti said most ppl were not aware of this.