If You Don't Understand An Item Follow Its Link For More Explanation
Cynthia is a very good program. It's also a very limited program. Some web designers with a passing knowledge of accessibility may think “If my site passes Cynthia, then my site is accessible.” Cynthia itself, being nothing but software does not understand what you meant to do or ought to have done. It has only a very specific set of things that it can check for; many of the accessibility problems that exist can't actually be tested for automatically. So manual checks are needed.
Each item listed in the report has a link to help information to references to the source in Section 508 and/or WAI. So if you don't understand a listed item follow its link for more explanation.
By far the most likely reason for lack of compliance is
the absence of ALTernate text for images. Making all the
images on your site accessible will get you a long way
toward an accessible site. It's pretty simple for Cynthia to
check to see if an image on a web page has alternative text
or not --it simply checks to see if there is an
alt attribute. However, this isn't sufficient,
because it doesn't tell you if it is an
alt attribute. For
alt text for a photo that is in a
tutorial web page on how to operate a cassette player could
be "cassette_power.jpg (342 bytes)" or it could be just
"image" or it could be "photo of the cassette player with
an arrow pointing to the power button" or something else
which isn't likely to be useful.
alt attribute text is used to
replace an image. That means that it
serves the same function as the image. It
is not a label for the image. This is not
an immediately obvious distinction and the last option in
the example above "photo of a cassette player with an arrow
pointing to the power button" might seem to work. In fact,
it might seem natural to assume that
alt is a
"label." It is not. The words used should be a text
equivalent and convey the same
information/serve the same purpose as the image. A more
alt attribute would be
"The cassette player's power button is the first button on
the right on the front of the unit." The aim is provide the
same information which the visual user sees.
Even though Cynthia has some automated "alt text quality reports", the program can only partially automate the checking process. The rest needs to depend upon human judgment. These "User Checks" rely upon you to answer questions regarding the pages you have tested. These checks are essential.