CASE statement Afterwards applied, although the order of the code is different (fade-out/fade-in onClick button event)

Your “wrong” code…

$w("#image1").hide(); 

$w.onReady(() => {
    $w("#button22, #button23, #button25").onClick(event => {
        $w("#image1").hide("fade", {"duration": 500}).then( ( ) => {
 let src;
 switch(event.target.id) {
 case "button22":
                src = "https://static.wixstatic.com/media/aaa.jpg";
 break;
 case "button23":
                src = "https://static.wixstatic.com/media/bbb.jpg";
 break;
 case "button25":
                src = "https://static.wixstatic.com/media/ccc.jpg";
 break;
            }
            $w("#image1").src = src;
            $w("#image1").show("fade", {"duration": 500});
        } );
    })

Correction…

$w.onReady(() => {
    $w("#button22, #button23, #button25").onClick(async(event) => {
 await $w("#image1").hide('fade')
 let src;
 switch(event.target.id) {
 case "button22":
                            src = await "https://static.wixstatic.com/media/aaa.jpg";
 break;
 case "button23":
                            src = await "https://static.wixstatic.com/media/bbb.jpg";
 break;
 case "button25":
                            src = await "https://static.wixstatic.com/media/ccc.jpg";
 break;
        }
        $w('#image1').src = src
        $w("#image1").show('fade')
    })
})