It is rightly said – “A picture is worth a thousand words”. The idea is also applied to web content. A well-written text document with interesting and appealing images would certainly engage users with the story and also the images that can complement the text documents render the article more meaningful and valuable.
Most search engines allow users to search for images independently and check for billions of pictures that can also be useful for driving a huge amount of traffic to your website.Thus, spending a little time and optimising the images for search engines paves the way for attracting a huge amount of traffic towards your blog or website.
The image optimization essentially involves better positioning of images in content, optimising for user experience and using the correct keywords for search engines. It would make the website friendly and there are strong chances that the website would be enjoyed more than the one without images. The significance of image optimization becomes crucial when web pages are image rich having a little text content.
Similar to search engine optimization for web pages, images are also optimised for higher search rankings in image search. The important aspects of an image optimization are explained in detail in the subsequent section.
1. ALT Tag
ALT attribute is what search engines recognize images what they are all about. It is the most important aspect of image optimization for search engines. Crawlers crawl the images by their image names and alt attributes. It is also important when the images are not loaded in the browser because of some reasons (slow internet speed or browser issues), in that case, alt tags are displayed over the un-displayed images to show what that image was all about. A screenshot is shown below for example
As most of the search engines including Google and Yahoo allow to search images separately, so optimizing the images for top positions in search results will drive users to your site through images. Alt tag should contain a proper description of the image including right keywords in it.
2. Image Title
While surfing on internet, you might see a lot of images on web pages. If you put cursor on those images if a text is displayed which tells users about the image. The text is known as image title. The title is used as a tooltip when the user hovers the mouse over the image. It is helpful for both users as well as search engines to get information about the image.
3. File Name
The file name of images is another significant fact in image optimization. Similar to URLs should have the keywords in page optimization, the image name should contain the proper keywords as it becomes the URL of the image. Also, file name of the image is considered while search engine crawlers crawl the images. Instead of just uploading the images with the default name like “420941_12410932771490.jpg” which does not add any information about the image, it should be renamed with a keyword-rich name like “image-title-example.jpg”. Also, the images should be placed in one folder, like “example.com/files/images”, instead of placing them in random folders throughout the website.
4. File Format
Choosing the wrong format for images will unnecessarily increase the size of the image while lower the visual quality. The most common extensions for web images are .jpg, .gif and .png. The preferred use of each format is depicted as described below:
Preferred use of .JPG Extension
It is best suited for images that have a wide range of colours while they do not have sharp transitions or fine edges. Because of its compression algorithm, it works best for Photographs.
Preferred use of .GIF Extension
The .gif images will be far less in file size until the image is limited in colour and there are large areas of the same colour. Best for circuits, diagrams, clip arts and shapes.
Preferred use of .PNG Extension
It is a Lossless Compression type and has a limited range of colours. Good for interfaces and text where a lossy file compression like .jpg would require to be saved at much higher quality to achieve the same look.
5. The right anchor text
If an image is linked to any webpage, anchor text plays an important role to rank for those keywords used in anchor text. For example, linking to an image using a generic term like “image” or “photo” or a file name that doesn’t use keywords doesn’t give search engines much meaningful information on what the image is about. Linking to an image with keywords is helpful to search engines as well as people visiting your site.
6. Relevancy with the content
And the last but important factor is the relevancy of the content and image attributes. The surrounding content should be related to the keywords the images optimized for. If the image file name, alt tag, anchor text, etc does not match with the content on the webpage, it may look spammy to search engines and chances will be less to rank the images higher.