Why does alt='''' should be written to print an image

Answer 1

alt means "alternate" . For some reason browser maynot be able to load the image, or the source (src) may pointing to invalid addresses . In that cases it will be helpfull for the end user to give an alternate text in the place of image.

Answer 2

it's not that alt is used to print image alt is an attribute which is the alternative description in case image fails to load