Custom Image Example with Toolkit
<mvt:item name="toolkit" param="customimagec|bigImage|l.all_settings:upsold_product:code|main|||1" />
<mvt:if expr="g.bigImage">
<img src="&mvt:global:bigImage;" alt="&mvt:upsold_product:name" />
<mvt:else>
<img src="no-image.jpg" />
</mvt:if>