procedure TMainForm.btnAppendClick(Sender: TObject);
begin
  if dlgOpenImage.Execute then
    fDBMultiBitmap.AppendImage( dlgOpenImage.Filename );
end;

# Step 1: Create a new table with the modified column length for Filename
cursor.execute("""
    CREATE TABLE IF NOT EXISTS NewImages (
        ID INTEGER,
        Filename varchar(255),
        Description memo,
        Image image,
        PRIMARY KEY(ID)
    );
""")

# Step 2: Copy data from the old table to the new table
cursor.execute("""
    INSERT INTO NewImages (ID, Filename, Description, Image)
    SELECT ID, Filename, Description, Image FROM Images;
""")

# Step 3: Drop the old table
cursor.execute("DROP TABLE Images;")

# Step 4: Rename the new table to the old table's name
cursor.execute("ALTER TABLE NewImages RENAME TO Images;")

# Commit the changes and close the connection
conn.commit()
conn.close()