Alternative text allows you to add a description to an image.
This is important for your website as search engine crawlers cannot see images, they rely on alternative text attributes to determine the relevance of an image to a search query.
Alternative text also helps make an image more likely to appear in a Google image search and is used by screen readers to provide context for visually impaired users.
If you search for used Audi for sale in Google images you will see examples of cars for sale.

The images above are well labelled with alt text or alternative text and will perform better in search results and encourage users to click through to your website. Your car dealer images will not be found in Google if not properly labelled,
Try to keep your alternative text to a simple, one-sentence description of what’s in the image.
Alternative Text and SEO
Quality, engaging and useful content is considered a prerequisite for search engine optimisation.
A car dealer website has by its nature a lot of text content and images.
It is important that these images are labelled with alt text.
This will have a positive impact on your SEO efforts and the performance of your website in search engines.
Our reports show if a website is using alt text correctly.
By reviewing websites in the industry that perform well you can alt text in action.