add alt text for images

invenio_theme_tuw/templates/semantic-ui/invenio_theme_tuw/footer.html

@@ -2,11 +2,11 @@
   <div id="logos">
       <div class="supportlogo">
           <a>powered by</a>
-          <a href="https://inveniosoftware.org/products/rdm/"><img src="/static/images/footer-logos/rdmlogo.png " /></a>
+          <a href="https://inveniosoftware.org/products/rdm/"><img src="/static/images/footer-logos/rdmlogo.png" alt="Logo of Invenio RDM" /></a>
       </div>
       <div class="supportlogo ">
           <a>enabled by</a>
-          <a href="https://forschungsdaten.at/fda/"><img src="/static/images/footer-logos/fair-data-austria.png " /></a>
+          <a href="https://forschungsdaten.at/fda/"><img src="/static/images/footer-logos/fair-data-austria.png" alt="Logo of the 'FAIR Data Austria' project" /></a>
       </div>
   </div>
   <nav class="footer">

invenio_theme_tuw/templates/semantic-ui/invenio_theme_tuw/frontpage.html

@@ -54,7 +54,7 @@ under the terms of the MIT License; see LICENSE file for more details.
       <div class="flip-card">
         <div class="flip-card-inner">
           <div class="flip-card-front">
-            <img src="static/images/features/upload-file.png">
+            <img src="static/images/features/upload-file.png" alt="icon displaying a cloud and a arrow pointing upwards." />
           </div>
           <div class="flip-card-back">
             Publish research outputs openly. A landing page provides information on your digital objects,
@@ -69,7 +69,7 @@ under the terms of the MIT License; see LICENSE file for more details.
       <div class="flip-card">
         <div class="flip-card-inner">
           <div class="flip-card-front">
-            <img src="static/images/features/magnifying-glass.png">
+            <img src="static/images/features/magnifying-glass.png" alt="icon displaying a magnifying glass" />
           </div>
           <div class="flip-card-back">
             Search datasets published by other users.
@@ -83,7 +83,7 @@ under the terms of the MIT License; see LICENSE file for more details.
       <div class="flip-card">
         <div class="flip-card-inner">
           <div class="flip-card-front">
-            <img src="static/images/features/rating.png">
+            <img src="static/images/features/rating.png" alt="icon displaying a tick and three stars which should represent a user rating." />
           </div>
           <div class="flip-card-back">
             Restrict access and share data by link, e.g. for peer-review of data underling publications.
@@ -97,7 +97,7 @@ under the terms of the MIT License; see LICENSE file for more details.
       <div class="flip-card">
         <div class="flip-card-inner">
           <div class="flip-card-front">
-            <img src="static/images/features/reuse.png">
+            <img src="static/images/features/reuse.png" alt="icon displaying two green arrows arranged in a circle." />
           </div>
           <div class="flip-card-back">
             Deposit your data to make it FAIR. The process can be automated with a use of APIs provided by
@@ -116,7 +116,7 @@ under the terms of the MIT License; see LICENSE file for more details.
     <div class="flip-card">
       <div class="flip-card-inner">
         <div class="flip-card-front light">
-          <img src="/static/images/planned-features/online-community.png">
+          <img src="/static/images/planned-features/online-community.png" alt="icon displaying a network of ideas and users." />
         </div>
         <div class="flip-card-back light">
           <a>Create your "Communities" with a collection of datasets and supplementary materials to collaborate with
@@ -129,7 +129,7 @@ under the terms of the MIT License; see LICENSE file for more details.
     <div class="flip-card">
       <div class="flip-card-inner">
         <div class="flip-card-front light">
-          <img src="/static/images/planned-features/git.png">
+          <img src="/static/images/planned-features/git.png" alt="icon displaying the github logo">
         </div>
         <div class="flip-card-back light">
           <a>Easily preserve your GitLab repository in TU Data and get a DOI for your code.</a>
@@ -141,7 +141,7 @@ under the terms of the MIT License; see LICENSE file for more details.
     <div class="flip-card">
       <div class="flip-card-inner">
         <div class="flip-card-front light">
-          <img src="/static/images/planned-features/analytics.png">
+          <img src="/static/images/planned-features/analytics.png" alt="icon displaying a bar and pie chart.">
         </div>
         <div class="flip-card-back light">
           <a>All uploads display standards compliant with usage statistics.</a>
@@ -153,7 +153,7 @@ under the terms of the MIT License; see LICENSE file for more details.
     <div class="flip-card">
       <div class="flip-card-inner">
         <div class="flip-card-front light">
-          <img src="/static/images/planned-features/team.png">
+          <img src="/static/images/planned-features/team.png" alt="icon displaying a group of three persons." />
         </div>
         <div class="flip-card-back light">
           <a>Open TU Data for cross-university and international collaboration.</a>

invenio_theme_tuw/templates/semantic-ui/invenio_theme_tuw/header.html

@@ -39,9 +39,8 @@
 
     <div id="signet">
       <a href="/">
-        <svg aria-label="TU Wien - Hauptseite" id="tuw-logo" role="img"
-             style="enable-background:new 0 0 97 97;"
-             version="1.1" viewBox="0 0 97 97" x="0px" xml:space="preserve"
+        <svg aria-label="TU Wien" id="tuw-logo" role="img"
+             style="enable-background:new 0 0 97 97;" viewBox="0 0 97 97" x="0px" xml:space="preserve"
              xmlns="http://www.w3.org/2000/svg" y="0px">
                         <g>
                             <path d="M86.5,1c5.2,0,9.5,4.3,9.5,9.5l0,76c0,5.3-4.3,9.5-9.5,9.5h-76C5.3,96,1,91.7,1,86.5l0-76C1,5.3,5.3,1,10.5,1