I need the fastest image upload in the Oracle BLOBs. I must make continual uploads of about 1000 images of 500K. What is the fastest way?

I made:
.....
/* qryInsertImage =
INSERT INTO IMAGE.KS_IMAGE_DATA_POKUS
(IMAGE_ID, DATA)
VALUES(:IMAGE_ID, EMPTY_BLOB())
RETURNING DATA INTO :DATA */

TLOBLocator *xLOBLoc;
AnsiString xFileName;
Connect();
for ( int n = 1; n <= 1000; n++ )
{
qryInsertImage->SetVariable("IMAGE_ID", n);
xLOBLoc = new TLOBLocator(OracleSession1, otBLOB);
qryInsertImage->SetComplexVariable("DATA", xLOBLoc);
qryInsertImage->Execute();
xFileName = "DicomFile" + AnsiString(n) + ".dcm";
xLOBLoc->LoadFromFile(xFileName);
delete xLOBLoc;
OracleSession1->Commit();
}
OracleSession1->LogOff();

Is it the fastest way?
Is this faster way then the TOracleDataSet? I think so, it does not create memory structures of all table rows as TOracleDataSet.
Have I to do COMMIT after every row? COMMIT clears rollback segments.
I think, creating and destroying the TLOBLocator is slow, can I reuse object?
How can I make physical parameters of Oracle table, the CHUNK, INITIAL, NEXT for instance?
Can I make directly upload of image without returning clause:
INSERT INTO IMAGE.KS_IMAGE_DATA_POKUS
(IMAGE_ID, DATA) VALUES(:IMAGE_ID, :DATA)
on Oracle 9.2. database?

Thank You, very much!