Instead of using $lob->savefile($form_data) for storing lob into oracle8 db, like is described in the php manual seccion oracle8 functions.
Use $lob->save(readf($form_data)) becaus function savefile doesn't store the whole lob in the orcale8 db just a part of it.

Here?s a short script for storing lob into oracle8 db
$sql  = "insert into fotos (id, dados, largura, altura, formato,tamanho)";
    $sql .= " values ($id, EMPTY_BLOB(), $largura, $altura, '$formato', $form_data_size)";
    $stmt = OCIParse($conn,"$sql returning dados into :lob");
    
    $lob = OCINewDescriptor($conn,OCI_D_LOB);
    OCIBindByName($stmt,":lob",$lob,-1,OCI_B_BLOB);
    OCIExecute($stmt,OCI_DEFAULT);
    
    if($lob->save(readf($form_data))){
       OCICommit($conn);
       echo "Blob successfully uploaded\n";
    } else {
       echo "Couldn't upload Blob\n";
    }

Where readf is a function for reading binary data
function readf($filename)
 {$fp = fopen($filename,"rb");
  $buffer = fread($fp,filesize($filename));
  fclose($fp);
  return $buffer;
 }

Another thing try to look at the function writetofile and fwrite a see the difrences when saving a lob into a file.
When using writetofile the carriage return (0A) is converted to (0D 0A) under win98.