magento-test/app/code/Magento/Csp/etc/csp_whitelist.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<csp_whitelist xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Csp:etc/csp_whitelist.xsd">
        <policies>
            <policy id="img-src">
                <values>
                    <value id="data" type="host">data:</value>
                </values>
            </policy>
        </policies>
</csp_whitelist>