design-themes/theme_bistro/views/snippets/s_image_text.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>

<template id="s_image_text" inherit_id="website.s_image_text">
    <!-- Section -->
    <xpath expr="//section" position="attributes">
        <attribute name="class" add="pt64 pb64" remove="pt32 pb32" separator=" "/>
    </xpath>
    <!-- Image -->
    <xpath expr="//img" position="attributes">
        <attribute name="class" add="img-thumbnail" separator=" "/>
        <attribute name="style" add="padding: 20px !important;" separator=" "/>
    </xpath>
</template>

</odoo>