Alt text stands for alternative text and is a short description of an image that helps search engines understand what the image is about, so they can show the image to the connected search results.
That is why it is very important from an SEO point of view to write text for all the images to improve the ranking of your pages.
How to write a good alt text?
To be able to select the right words for your text, you must pay attention to the keywords connected to the page where the image will be shown.
You should try to be specific and avoid using the terms ‘the image of’ or ‘the picture of’. Remember this is just going to have an effect on SEO so visitors won’t read it.
Also, remember not to repeat what you already mentioned inside the page as alt text for the images.