You should try setting a variable outside of the loop, then accumulate this value within the loop so that you can determine how many times the loop is occurring. You could set it up like so:
$the_deleted_filenames = "";
$the_deleted_filenames .= $row_photosRS['PhotoFilename'] . ", ";
$WA_DeleteFileResult1 = false;
$WA_DeleteFileResult1 = WA_FileAssist_DeleteFile("../../pawpics_gallery/".$_SESSION['pawsid'] ."/", "".$row_photosRS['PhotoFilename'] ."");
} while ($row_photosRS = mysql_fetch_assoc($photosRS));
die("the deleted file names are: " . $the_deleted_filenames);
Give this a try to see the names of the files that are attempted to be deleted.