Always take the time to name your images with relevant titles that describe the photo and the content in the photo. Google cannot search unlayered image files (Jpegs, PNG and Tiff’s) but it will spider meta data, image descriptions and image file names.
Use media files in collaboration with, and in the same context as your content copy. Media content – movie and audio files count as well – teamed with good authentic copy that tells a relevant story will be ranked higher by Google, Bing and other search engines.
The closer your content matches a Google search, the higher authority Google will give the content and increase your chances of being ranked higher in their search rankings.
In summary, be sure to include good relevant content with appropriately named files and titles and descriptions.