To get more traffic from search engines you have to optimize the content of your site accordingly. Other than text optimization you should go for image optimization to get traffic from Google Image Search. The basic things you should consider in optimizing images are "alt" attribute and image names.
Here are some best practices you should follow:
Use Short, but Detailed Filenames and Alt Text
Don’t use generic filenames like "image1.gif", "pic.gif", "1.jpg". Tell the search engine what this image is about like if you are embedding a logo of Google in content then the filename should be "google-logo.jpg". And avoid writing extremely lengthy names.
The "alt" attribute allows you to specify alternative text for the image if it cannot be displayed for some reason. Suppose if user is viewing your site on a browser that doesn’t support images the alt text will tell him about the image. If you are using image as a link, the alt text will be act similarly to the anchor text of a text link. There is one mistake i was doing before, stuffing keywords into alt text, which you should avoid.
Store Files in Same Directory Using Common File Formats
Instead of saving images in different directories and sub directories, consider having them all in one common directory (e.g. pelfusion.com/wp-content/uploads). Just to have simple path to your images.
Use commonly supported filetypes – Most browsers support JPEG, GIF, PNG, and BMP image formats.
Supply an Image Sitemap File
I recently implemented this on PelFusion. Structure of Image Sitemap is similar to the XML Sitemap and it gives more information to Googlebot. Sitemap uses some image tag definitions, which are important for Google to extract information. If you are running WordPress it’s very simple to generate Image Sitemap using Google XML Sitemaps but for other sites you can utilize Free XML Sitemap Generator.