Image non empty acc name - revised PR

[dd8]

The PR replaces https://github.com/act-rules/act-rules.github.io/pull/1208

Reason for new PR: rule has been renamed, and many changes from original PR were merged in https://github.com/act-rules/act-rules.github.io/pull/1300

This PR:

• restricts the applicability to elements that render an image (to make <img/> and <div style='background-image:none'> inapplicable because they have no visual rendering, and are not voiced)
• adds <img/> as an inapplicable example
• adds additional failed examples like <img srcset='...'/>

Closes issue(s):

• closes issue described here https://github.com/act-rules/act-rules.github.io/issues/1124#issuecomment-578042900

Need for Final Call: This will require a 2 week Final Call

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[dd8]

I don't have repo rights to do these:

• Add yourself (and co-authors) as "Assignees" for PR.
• Add label to indicate if it's a Rule, Definition or Chore.
• Optionally request feedback from anyone in particular by assigning them as "Reviewers".

Can someone with repo maintainer rights do them? Thanks.

[dd8]

I think that's all the requested changes addressed. I think it's important to reference the HTML represents nothing definition somewhere in the rule, but I'm not convinced doing it from the examples is the right place.