This is a TYPO3 ViewHelper which allows you to insert a remote image with all the possibilities of the normal image ViewHelper.
{namespace dcd=DCD\DcdExtbaseEssentials\ViewHelpers}
<dcd:image.remote src="http://www.dachcom.com/fileadmin/templates/images/interface/logo.png" alt="" />
This ViewHelper doesn't take care of the temporary files. You have to take care of them for yourself. They are located under "typo3temp/ImageRemote/"