ALT text is the description of the image and it is supposed to provide the meaning/message of it. Therefore, the ALT text must be descriptive so that when the image load fails, the reader can determine the image's purpose.

To add the good ALT text, you need to note down these tips:

ALT text is the description of the image and it is supposed to provide the meaning/message of it. Therefore, the ALT text must be descriptive so that when the image load fails, the reader can determine the image's purpose.

An undescribed species of text can confuse readers as well as search engines.

• Don't add ALT text to all images

Your website might have several images just for decoration, that don’t serve any informational purpose. It will be annoying for users with screen readers if you add meaningless ALT text for these decorative images. In this case, you can use a null ALT tag <alt="">, which will be ignored by screen readers.

• ALT text should be accurate and concise

ALT text needs to focus on the appearance and functions of the image. And this is also the reason they shouldn't be lengthy. For example, "strawberry cheesecake with cream" is enough to describe an image, instead of "there is a picture of a beautiful and delicious strawberry cheesecake with cream on the table".