The gray area is a matter of scale and purpose. If you have a small business which serves as specific market it's a good idea to make the site as user and disability friendly as possible. If, however, your market serves segments with a likeliness to have various handicaps or disabilities you should address that with an ADA Compliance review of the site. Also consider the scale and purpose of an organization. Publicly traded large businesses need to concern themselves more than a single location family owned retailer and if someone sues your flower shop because the text was too small or didn't have "image alt tags" causing them distress... That's pretty frivolous and would likely not stand.
The Department is evaluating whether promulgating regulations about the accessibility of Web information and services are necessary and appropriate. Such an evaluation will be informed by an additional review of data and further analysis. The Department will continue to assess whether specific technical standards are necessary and appropriate to assist covered entities with complying with the ADA.
Because they only read text, screen readers and refreshable Braille displays cannot interpret photographs, charts, color-coded information, or other graphic elements on a webpage. For this reason, a photograph of a mayor on a city’s website is inaccessible to people who use these assistive technologies, and a blind person visiting the website would be unable to tell if the image is a photo, a logo, a map, a chart, artwork, a link to another page, or even a blank page.
The Department of Justice may file lawsuits in federal court to enforce the ADA Compliance, and courts may order compensatory damages and back pay to remedy discrimination if the Department prevails. Under title III, the Department of Justice may also obtain civil penalties of up to $55,000 for the first violation and $110,000 for any subsequent violation of ADA Compliance.
The words in the tag should be more than a description. They should provide a text equivalent of the image. In other words, the tag should include the same meaningful information that other users obtain by looking at the image. In the example of the mayor’s picture, adding an “alt” tag with the words “Photograph of Mayor Jane Smith” provides a meaningful description.