Image filenames and alt tags

Image names and image alt tags are an example of a ranking factor that is afforded lower weight in search rankings, that is, wordpress-expert.jpg as a filename in an attempt to rank for WordPress expert. Certainly, image names alone will never make anyone rank for any term or phrase that is highly competitive. However, image names and alt tags can be effective as supplemental weight for search terms when the more important elements such as title tags and heading tags are highly focused and in accord.