If you want your photographs, illustrations and screenshots to rank well in Google Images, here are some simple but useful SEO tips that may help you do better in Google for your images.
1. Try placing your images higher up on a page as most users won’t scroll beyond the fold. Search engines love pages that are friendly to human users.
2. Specify the height and width for images as then a web browser can render web pages even before images are downloaded. Specifying image dimensions will speed up page loading and thus improve the user experience.
3. Have a separate landing page for every image and make the page has a description title caption and if possible, ratings and comments to help Google know if users are really liking that picture.
4. When internal-linking to your own pages that contain photographs, use descriptive anchor text – like “photos of mexico trip.”
5. Take action against sites that are taking your images as Google will only show one image (when there are multiple similar images for a search query) and you therefore need to let Google know that you are the original owner.
More on Google Webmasters.