Fix alt attributes in image tags on OSCSA Website main page

index.html

@@ -135,7 +135,7 @@ <h3 class="section-title">About Us</h3>
           <div class="row">
 
             <div class="col-lg-6 about-img">
-              <img src="assets/img/landing/os.webp" alt="">
+              <img src="assets/img/landing/os.png" alt="The Turing way project illustration by Scriberia">
             </div>
 
             <div class="col-md-6 about-content">
@@ -429,16 +429,16 @@ <h3 class="section-title">UNESCO Recommendation on Open Science</h3>
         <div class="row">
           <div class="col-md-3">
             <div class="profile">
-              <div class="pic"><img src="assets/img/portfolio/UNISCO.webp" alt=""></div>
+              <div class="pic"><img src="assets/img/portfolio/UNISCO.jpeg" alt="UNESCO logo"></div>
             </div>
           </div>
           <div class="col-md-9">
             <div class="quote">
-              <b><img src="assets/img/quote_sign_left.png" alt=""></b> Supporting scientists and other societal actors in accumulating and
-               using open data resources in a transdisciplinary mode to maximize scientific, social, economic, and cultural benefits,
-                and stimulate the creation of hybrid disciplinary collaborative spaces where scientists from different disciplines 
-                interact with software developers, coders, creatives, innovators, engineers, and artists, among others. 
-                <small><img src="assets/img/quote_sign_right.png" alt=""></small>
+              <b><img src="assets/img/quote_sign_left.png" alt="Quotation Marks"></b> Supporting scientists and other societal actors
+              in accumulating and using open data resources in a transdisciplinary mode to maximize scientific,
+              social, economic and cultural benefits, and stimulate the creation of hybrid disciplinary
+              collaborative spaces where scientists from different disciplines interact with software developers,
+              coders, creatives, innovators, engineers and artists, among others. <small><img src="assets/img/quote_sign_right.png" alt="Quotation Mark"></small>
             </div>
           </div>
         </div>
@@ -545,10 +545,10 @@ <h3 class="section-title">Supporters</h3>
         <div class="section-title-divider"></div>
 
         <div class="column">
-          <img src="assets/img/logo/css.png" alt="" width="400" class="center">
+          <img src="assets/img/logo/css.png" alt="CS&S logo" width="400" class="center">
               <!-- </div>
         <div class="column"> -->
-          <img src="assets/img/logo/outreachy.png" alt="" width="420" class="center">
+          <img src="assets/img/logo/outreachy.png" alt="Outreachy logo" width="420" class="center">
         <!-- </div> -->
         </div>
         <!-- <p> <img src="assets/img/logo/outreachy.png" alt="" width="400"></p>