I think I've got this working with the additions of:

$images[$image]["large"]["delete_link"] = ($dirread[DIR_FS_CATALOG_IMAGES . "large/" . $p["dirname"]] == true && IMFileIsWriteable($filename_large) ? $partlink. "&actcnt=" . ($_SESSION["actcnt"] + 1) . "&IMaction=deletefile&filename=" . urlencode('large/' . $p["dirname"] . $p["filename"] . IMAGE_SUFFIX_LARGE . "." . $p["extension"]) . "\" onclick=\"return confirm('" . IM_CONFIRM_SINGLE_DELETE . "');\" />". IM_IMAGE_DELETE . "</a>" : "");

at line 358 of the function_image_manager.php file.

Please let me know if this is an acceptable solution or if this will cause other problems?