Turning off the style sheets and images (with the alt text showing) is a good way to find out if your static content stands on its own or not. When the content is stripped bare like this, it is sort of how a screen reader "sees" it.
Avoid Referencing Color, Size, Location, Position, or Sound in Instructions or Help Information:
Any time we reference size, location, position, or sound in information, we're relying on the presence of a specific sense (or senses) on the part of our user, which he or she may not have.
... the larger area represents ...
... the alert will display when ...