diff --git a/.github/config.yml b/.github/config.yml
index dd9685382145..bf4285c74bef 100644
--- a/.github/config.yml
+++ b/.github/config.yml
@@ -20,6 +20,6 @@ firstPRMergeComment: >
 
   <a href="https://www.jenkins.io/participate/" target="_blank">
    <picture>
-     <img width="600" src="https://raw.githubusercontent.com/jenkinsci/jenkins/master/.github/images/jenkins-welcome.svg">
+     <img width="600" alt="Participate in and contribute to the Jenkins project" src="https://raw.githubusercontent.com/jenkinsci/jenkins/master/.github/images/jenkins-welcome.svg">
    </picture>
   </a>
diff --git a/core/src/main/resources/hudson/diagnosis/MemoryUsageMonitor/index.jelly b/core/src/main/resources/hudson/diagnosis/MemoryUsageMonitor/index.jelly
index bb0efd378ea8..e4c9e804dbd2 100644
--- a/core/src/main/resources/hudson/diagnosis/MemoryUsageMonitor/index.jelly
+++ b/core/src/main/resources/hudson/diagnosis/MemoryUsageMonitor/index.jelly
@@ -61,7 +61,7 @@ THE SOFTWARE.
           </j:otherwise>
         </j:choose>
       </div>
-      <img src="graph?type=${type}&amp;width=500&amp;height=300" />
+      <img src="graph?type=${type}&amp;width=500&amp;height=300" alt="${%memory usage monitor graph}" />
     </l:main-panel>
   </l:layout>
 </j:jelly>
diff --git a/core/src/main/resources/hudson/model/DirectoryBrowserSupport/dir.jelly b/core/src/main/resources/hudson/model/DirectoryBrowserSupport/dir.jelly
index a50dd9b46cf9..bea0801ec867 100644
--- a/core/src/main/resources/hudson/model/DirectoryBrowserSupport/dir.jelly
+++ b/core/src/main/resources/hudson/model/DirectoryBrowserSupport/dir.jelly
@@ -50,13 +50,13 @@ THE SOFTWARE.
             ${%No files in directory}
            <j:if test="${showSymlinkWarning}">
              <p>
-                <img id="symlinkalert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" />
+                <img id="symlinkalert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" alt=""/>
                ${%Symlinks are hidden}
              </p>
             </j:if>
            <j:if test="${showTmpDirWarning}">
              <p>
-               <img id="tmpdiralert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" />
+               <img id="tmpdiralert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" alt=""/>
                ${%Tmp directories are hidden}
              </p>
             </j:if>
@@ -124,13 +124,13 @@ THE SOFTWARE.
            </table>
            <j:if test="${showSymlinkWarning}">
              <p>
-                <img id="alert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" />
+                <img id="alert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" alt=""/>
                ${%Symlinks are hidden}
              </p>
             </j:if>
            <j:if test="${showTmpDirWarning}">
              <p>
-                <img id="alert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" />
+                <img id="alert" src="${imagesURL}/svgs/warning.svg" width="16" height="16" alt=""/>
                ${%Tmp directories are hidden}
              </p>
             </j:if>
diff --git a/core/src/main/resources/jenkins/model/Jenkins/_404.jelly b/core/src/main/resources/jenkins/model/Jenkins/_404.jelly
index 4605b5926760..d7433188a87f 100644
--- a/core/src/main/resources/jenkins/model/Jenkins/_404.jelly
+++ b/core/src/main/resources/jenkins/model/Jenkins/_404.jelly
@@ -34,7 +34,7 @@ THE SOFTWARE.
         <l:header />
         <l:main-panel>
             <h1 style="text-align: center">
-                <img src="${imagesURL}/rage.svg" height="179" width="154"/>
+                <img src="${imagesURL}/rage.svg" height="179" width="154" alt=""/>
                 <span style="font-size:50px"><st:nbsp/>${%Oops!}</span>
             </h1>
             <div id="error-description" style="text-align: center">
diff --git a/core/src/main/resources/jenkins/model/Jenkins/_404_simple.jelly b/core/src/main/resources/jenkins/model/Jenkins/_404_simple.jelly
index c6a876bb2955..520dd8482b00 100644
--- a/core/src/main/resources/jenkins/model/Jenkins/_404_simple.jelly
+++ b/core/src/main/resources/jenkins/model/Jenkins/_404_simple.jelly
@@ -48,7 +48,7 @@ THE SOFTWARE.
             </head>
             <body style="font-family: system-ui, sans-serif">
                 <h1 style="text-align: center">
-                    <img src="${imagesURL}/rage.svg" height="179" width="154" style="vertical-align: middle"/>
+                    <img src="${imagesURL}/rage.svg" height="179" width="154" style="vertical-align: middle" alt=""/>
                     <span style="font-size:50px"><st:nbsp/>${%Oops!}</span>
                 </h1>
                 <div style="text-align: center">
diff --git a/core/src/main/resources/jenkins/model/Jenkins/oops.jelly b/core/src/main/resources/jenkins/model/Jenkins/oops.jelly
index 28238c660253..fabdd175cbcb 100644
--- a/core/src/main/resources/jenkins/model/Jenkins/oops.jelly
+++ b/core/src/main/resources/jenkins/model/Jenkins/oops.jelly
@@ -32,7 +32,7 @@ THE SOFTWARE.
     <l:header />
     <l:main-panel>
         <h1 style="text-align: center">
-          <img src="${imagesURL}/rage.svg" height="179" width="154"/> <span style="font-size:50px"><st:nbsp/>${%Oops!}</span>
+          <img src="${imagesURL}/rage.svg" height="179" width="154" alt=""/> <span style="font-size:50px"><st:nbsp/>${%Oops!}</span>
         </h1>
         <div id="error-description">
           <h2 style="text-align: center">${%problemHappened}</h2>
diff --git a/core/src/main/resources/lib/layout/dropdowns/custom.jelly b/core/src/main/resources/lib/layout/dropdowns/custom.jelly
index 4b9d18fc59b6..b563f95b74cd 100644
--- a/core/src/main/resources/lib/layout/dropdowns/custom.jelly
+++ b/core/src/main/resources/lib/layout/dropdowns/custom.jelly
@@ -31,7 +31,7 @@ THE SOFTWARE.
 
         <![CDATA[
             <dd:custom>
-              <img src="jenkins.svg" />
+              <img src="jenkins.svg" alt=""/>
             </dd:custom>
         ]]>
     </st:documentation>