constructor

import os
import sqlite3
from contextlib import closing
from PySide2.QtCore import QByteArray, QBuffer, QIODevice
from PySide2.QtGui import QImage

import timeit

source = QImage('test.png')

# print(timeit.timeit(lambda: source.save('testaaa.png'), number=100))

bits = source.constBits()
width = source.width()
height = source.height()
bytes_per_line = source.bytesPerLine()
format = source.format()

db_file = 'test2.db'

if os.path.isfile(db_file):
    os.remove(db_file)

with closing(sqlite3.connect(db_file)) as conn:
    cursor = conn.cursor()
    cursor.execute('create table images (width int, height int, bytes_per_line int, format int, bytes blob)')
    for i in range(100):
        cursor.execute(
            'insert into images (width, height, bytes_per_line, format, bytes) values (?, ?, ?, ?, ?)',
            [width, height, bytes_per_line, int(format), bits])
    conn.commit()

with closing(sqlite3.connect(db_file)) as conn:
    cursor = conn.cursor()
    def load():
        for i, (width, height, bytes_per_line, format, bytes) in enumerate(cursor.execute('select width, height, bytes_per_line, format, bytes from images')):
            image = QImage(bytes, width, height, bytes_per_line, QImage.Format(format))
            # print(len(image.bits()), image.format())
            image.save(f'test_out/test_out_{i}.png')
    print(timeit.timeit(load, number=10))
    # load()