Alternate Proposal: Providing Human-Parseable and Machine-Processible Textual Alternatives and Markers for Static Images (GreggV)

Case 1: Image Needs alt, Author Provides It

 
        <img src="123.jpg" alt="Photo of my granny">
   OR 
       use labelledby   
   AND (if and only if needed)  
        describedby  
 

A 'Text alternative' is provided. Different alternatives are possible.

Case 2: Author Specifies the Image Should be Ignored

 
 ariarole="presentation"    AND/OR     alt=""    is used
 

Case 3: Image Needs alt, Author Can't/Won't Provide It, Also Doesn't Care If Code is Valid

 
<img src="123.jpg"> 
 

Case 4: Image needs text alternative, author can't/won't provide it, but does want code to be valid

 
      ALTNEEDED  is used instead of ALT
 

Content is VALID if ANY of the following is true

• ALT="<text alternative">
• ALT=""
• ALTNEEDED
• labelledby

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