5709a7858d5c197721be66d5218a79124abadb70
lrnassar
  Tue Mar 17 08:46:31 2026 -0700
Adding alt text to images across static documentation pages, CGI headers, markdown docs, and Pandoc templates. Content images receive AI-generated descriptive alt text; decorative images (icons, spacers, toggles) receive alt="" per WCAG best practice. Also adds Image Descriptions section to the accessibility page, and fixes Pandoc Lua writers to output alt attributes. 67 files, covering help docs, news archive, ENCODE pages, portal pages, and session examples. refs #37254

diff --git src/hg/htdocs/covid19.html src/hg/htdocs/covid19.html
index 2ee38b32a2c..94b1505ff24 100755
--- src/hg/htdocs/covid19.html
+++ src/hg/htdocs/covid19.html
@@ -75,31 +75,31 @@
 </div>
 
 <style>
 img {
     width: 100%;
     margin: 15px 0 !important;
 }
 </style>
 
 <div class="row">
 
     <!-- Genome browser -->
     <div class="col-md-6">
         <h2>UCSC Genome Browser view of SARS-CoV-2 genomic datasets</h2>
             <a href="/cgi-bin/hgTracks?db=wuhCor1" target="_blank">
-                <img src="/images/sarsCov2SpikeProteinsSession.png"></a>
+                <img alt="Genome Browser session showing SARS-CoV-2 spike protein annotations, conservation, and variant tracks" src="/images/sarsCov2SpikeProteinsSession.png"></a>
       <br>
         Video tutorial: Using the <a href = http://bit.ly/ucscVid20 
         target = _blank>coronavirus browser</a>.
     </div>
 
     <!-- Cell browser -->
     <div class="col-md-6">
         <h2>COVID-19 and Lung gene expression data in the UCSC Cell Browser:</h2>
             <p>COVID-19 Datasets:
             <ul>
               <li><a href="https://covid19-balf.cells.ucsc.edu"
               target="_blank">Bronchoalveolar Immune Cells in COVID-19</a>
               <li><a href="https://covid-airways.cells.ucsc.edu"
               target="_blank">COVID-19 Airways</a>
               <li><a href="https://covid19-influenza-response.cells.ucsc.edu"
@@ -145,31 +145,31 @@
         those genomes came from.
         UShER is the only available method that can do this in &quot;real time&quot;.
         Our tool places genomes onto a comprehensive global phylogeny of more than 80,000
         virus genomes in less than one second.
         More information about UShER can be found on the UCSC news article,
         <a href="https://news.ucsc.edu/2021/05/coronavirus-variants.html">New tools enable rapid
         analysis of coronavirus sequences and tracking of variants</a>. The number of genome
         sequences available has increased to 5.6 million since the article was initially published
         with 1.2 million sequences on May 2021. 
       </p>
       <p>
         <div style='float:left; margin-right: 10px;'>
 
         <!--#if expr="${SERVER_NAME} = /-china/" -->
             <a href='../../../videos/humQ1NyZOUM.mp4'>
-            <img style="width:267px; height:250px" src=../../images/videoIcon.png></a>
+            <img alt="" style="width:267px; height:250px" src=../../images/videoIcon.png></a>
         <!--#else -->
         <iframe width="267" height="150" src="https://www.youtube.com/embed/humQ1NyZOUM?rel=0" 
         frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" 
         allowfullscreen></iframe> </p>
         <p> Visit our <a href="https://www.youtube.com/channel/UCQnUJepyNOw0p8s2otX4RYQ/videos"
         target="_blank">YouTube channel</a> for more videos.
         <!--#endif -->
         </div>
 
         The <a href='https://www.cdc.gov/advanced-molecular-detection/php/training/'
                target=_blank>CDC COVID-19 Genomic Epidemiology Toolkit</a>
         now includes a training module for UShER!
         <!--#if expr="$SERVER_NAME = /-china/" -->
         Module 3.3 includes a <a href='../videos/humQ1NyZOUM.mp4' target=_blank>video</a>,
         <!--#else -->