RankWatch Community Forum

Both are used to describe the image but they are actually quite different. Alt attributes are for search engine crawlers; however, title tag is for viewers. 

The alt tags are those who are blind. Alt tag is used to crawl the image on the website as search engine can’t read the image. This alt tag is used as an alternative text for the image.  Alt attribute shows when image is not appeared in the browser. ALT text is used to drive more image search traffic.

Title attributes provides supplementary information of an image; search engines do not index them. Title attributes do not help to improve seo but it helps user who is viewing the page.

So, ALT tag has potential benefits of SEO, TITLE attribute does not.