As the new URI-to-resolve form "metadata?contentId=defaultWebContent://xxx" was introduced by fixing issue CMS-1951, it's valid to write:

<xsl:variable name="photo-path" select="concat(metadata/photo/@path, '?contentId=', $contentId)"/>
<img src="{resolver:resolveBoundedImage(metadata/photo/@type, $photo-path, 400, 300)}"/>

This introduces a problem when the metadata is either an uploaded file or a resource (when using the external-or-resource-image widget): in case of a resource, the resolver is given a URI of the form "resource://resourceId?contentId=defaultWebContent://xxx", which makes it crash.

Maybe "?" and all that follows should be ignored by the resolvers who doesn't need it...