While applying Search Engine Optimization to a web page increases its prominence in the result pages of search engines like Google, SEO is usually thought in terms of creating outgoing links to external websites and using the same keywords repeatedly throughout the content text. However, at least one out of every three searches carried out on Google are image searches, and Google relies on SEO that has been applied onto images in order to determine which images should be displayed on the highest segments of relevant searches.
Because a search engine cannot visually parse an image the way human eyes can, Google may use any number of text elements surrounding the image in order to estimate whether it is a relevant image for searches. Besides the file name and the alt attribute, it appears that Google pays particular attention to the contents of the caption underneath the picture. The web page itself is also taken into consideration; the URL and the title element both help to establish for search engines whether there is further context to an image being on that page, and so does the other content text in the close vicinity of where on the page it is posted.
Apparently, if an image presented lower on a search result’s page gets enough clicks, it will be shifted into a higher position because of its proven popularity. This is a way in which a highly engaging image can be expected to take its place alongside other, equally engaging images in image searches even if it ranks low on search result pages at first.
Further factors that determine whether an image will quickly appear highly in search results include whether it does not have a lopsided width-to-height ratio and whether its overall dimensions are not overly small or large. One way that an image can directly benefit from being very large, however, is if it is intended to be searched by browsers looking for desktop wallpapers and the page the image is hosted on is clearly presenting itself as a wallpaper repository.
Finally, whether the website itself ranks highly in search engine results because of its own, traditional SEO seems to tell Google that the images hosted on it should be considered relevant among similar images that might be hosted by less prominent sites. Separately, if the image in question is embedded across multiple web pages separate from where it first appeared, that likely has a direct and positive impact on the picture’s perceived relevance.
All of the above factors are what a site owner hoping to get an image to appear near the top of search results needs to pay due consideration to by default. However, there is also the matter of being sure to associate only the proper keywords with images. There exist keyword research tools that allow the user to determine how likely an image will rank in a search for certain keywords in the context of specific markets. After determining that entering a specific keyword does cause similar images to appear in the search results, the site owner should repeat the process until he or she has anywhere between five and twelve keywords that all relate to the same image. Those keywords should then be incorporated into the text elements connected to and surrounding the image.