PP-3554 - update alt texts

Author: jonheslop

source/self-service-payments.html.erb

@@ -40,15 +40,15 @@ title: Self service payments - GOV.UK Pay
       <h2 class="heading-medium">Setting up a payment link</h2>
       <p>A payment link is quick and easy to set up and is ready to use right away. You don’t need any technical knowledge to create a payment link. You can create a payment link for a single user or make it reusable for all your users.</p>
 
-      <img class="content-section__image" src="/pay-product-page/images/payment-link-demo.gif" alt="Example of how the payment link is generated automatically from the title">
+      <img class="content-section__image" src="/pay-product-page/images/payment-link-demo.gif" alt="Example of creating a payment link and how the title is used to generate the payment link website address.">
 
       <p>Add the payment link where your users can see it, like in a paper form, letter or email - or even on your website.</p>
 
-      <img class="content-section__image" src="/pay-product-page/images/self-service-payments-example.svg" alt="Examples of a payment link on a paper form or on a web page.">
+      <img class="content-section__image" src="/pay-product-page/images/self-service-payments-example.svg" alt="Examples of a payment link on a paper form or on an email.">
 
       <p>When your users access your payment link, they’ll be able to make an online card payment. Your users will receive a payment reference number and a confirmation email.</p>
 
-      <img class="content-section__image" src="/pay-product-page/images/self-service-payments-flow.svg" alt="Screenshots showing the first and last pages of the payment link user journey.">
+      <img class="content-section__image" src="/pay-product-page/images/self-service-payments-flow.svg" alt="Example of the payment amount and confirmation pages of the payment link user journey.">
 
       <h2 class="heading-medium">Get started with self service payments</h2>