The point here is that the image appears on the Twitter card, not necessarily on the website. The url for the Twitter card image can be found in the <headsection of the website (so not visible). Here's the snippet:
<meta name="twitter:card" content="summary_large_image" />
<meta name="twitter:description" content=""I'm asking you to believe. Not in my ability to create change—but in yours." President Barack Obama" />
<meta name="twitter:title" content="obama.org" />
<meta name="twitter:site" content="@ObamaFoundation" />
<meta name="twitter:image" content="https://www.obama.org/wp-content/uploads/053020_GeorgeFloyd_Protests_Chicago_IL_CD_1588-scaled.jpg" />
<meta name="twitter:creator" content="@ObamaFoundation" />