We can make our images crawlable by adding Title and alt attribute. These things works better for SEO..
Optimizing images involves using the "Alt" attribute when adding images to your site. Since Google Crawlers cannot read images, the 'Alt' key is what tells Google to crawl your site or page.
making your images light in weight will make them load faster in the user's browser so they won't have to wait for the image to load, and as the others said adding an alt tag can help the visually impaired understand what it's about.
If you want to see a tutorial how to optimize your photos check the article that i have send you on Pm cause i can not post here yet. It is in romanian but you can translate with Google Cheers
Optimizing images for the web is a tricky business. but this is an important step, I see from any web most of the time burden from the image.
You need to use the ALT tag to describe with the image you placed is about. Very easy to do. Just add alt="DESCRIPTION OF THE IMAGE GOES HERE" in your IMG meta tag.
Use proper alt tags, don't use too large images(file size), name the images properly. For example if you use a image of a car dont name it as "DSC1001" name it properly as "Audi-A4".
hi friend you use it alt tag and also adding title or keyword use because your image Google crawler only for check Alt tag images. no any other.
In terms of SEO, you can optimize ALT attributes and image filenames to match / include your keywords.
Image optimization means giving alt tag to the images. Alt tag means a title for images with will appear on the tool tip of the images. You can use targeted keywords in the alt tags...
mainly that's reducing image sizes to accelerate loading. there are also more advanced techniques such as combining images into one single large imagemap and displaying sprites (parts of that imagemap). stackoverflow does that with most of their graphics, for example.