Apply suggestions from code review

Co-authored-by: Hugo van Kemenade <[email protected]>

Author: cmaureir

src/content/pages/guidelines.mdx

@@ -78,7 +78,7 @@ backup of anything you need rather than relying on the internet: while we do hav
 cables on the podiums, Murphy has a special nose for materials needed during live sessions.
 
 <div class="flex gap-4 max-w-[800px]" >
-  <Image src={speakerPhoto} alt="Speaker photo" class="w-[60%] border-4 border-white rounded-lg shadow-lg" />
+  <Image src={speakerPhoto} alt="A speaker behind the podium" class="w-[60%] border-4 border-white rounded-lg shadow-lg" />
 </div>
 
 ## Making your session accessible for everyone
@@ -142,7 +142,7 @@ there, they are likely to have just popped out, so don’t despair! Come back un
 cable if you want to check the set up for your presentation.
 
 <div class="flex gap-4 max-w-[800px]" >
-  <Image src={posterPhoto} alt="Speaker photo" class="w-[60%] border-4 border-white rounded-lg shadow-lg" />
+  <Image src={posterPhoto} alt="People reading a poster" class="w-[60%] border-4 border-white rounded-lg shadow-lg" />
 </div>
 
 ## Preparing for any technical difficulties
@@ -201,7 +201,7 @@ time, your final number of attendees is likely to be smaller than this.
 </div>
 
 <div class="flex gap-4 max-w-[800px]" >
-  <Image src={helperPhoto} alt="Speaker photo" class="w-[60%] border-4 border-white rounded-lg shadow-lg" />
+  <Image src={helperPhoto} alt="A tutor helping a tutorial attendee at their laptop" class="w-[60%] border-4 border-white rounded-lg shadow-lg" />
 </div>
 
 ## Specific advice for tutorials