OSError when read BMP

I generate some bmp image from cifar lmdb database using opencv. But when reading bmp, exception throws out: “OSError: Unexpected value read!”

import sensor, image, time

# Still need to init sensor
sensor.reset()
# Set sensor settings
sensor.set_contrast(1)
sensor.set_gainceiling(16)

# Set sensor pixel format
sensor.set_framesize(sensor.QQVGA)
sensor.set_pixformat(sensor.GRAYSCALE)

# Load image
img = image.Image("/viscifar/rgb.bmp")

# Add drawing code here.
# img.draw_line(...)

# Flush FB
sensor.flush()

# Add a small delay to allow the IDE to read the flushed image.
time.sleep(100)

Hi, our BMP file reading code is extremely old and needs to be redone. I haven’t had time for it yet however. Please generate the BMP file using GIMP and set the BMP file mode in GIMP to RGB565. You can select RGB565 under the advanced information tab.