Hi,

This code is used for the CSV file importing, so you can export the image field and external_id from v12 after creating a script for importing the images :

Create a wizard and the wizard.py like this

from odoo import models, fields
import base64
import io
import csv


class DynamicImageField(models.TransientModel):
    _name = 'import.photo'
    _description = 'Import Photo'

    file = fields.Binary('File')

    def import_photo(self):

        csv_data = base64.b64decode(self.file)

        data_file = io.StringIO(csv_data.decode("utf-8"))

        csv_reader = csv.reader(data_file, delimiter=',')
        keys = ['id', 'image'] # these are the csv file header , we only take the external id and the image filed(binary)
        file_reader = []
        file_reader.extend(csv_reader)
        for i in range(len(file_reader)):
            field = list(map(str, file_reader[i]))
            values = dict(zip(keys, field))
            if values:
                if i == 0:
                    continue
                else:
                    product = self.env.ref(values['id'])
                    product.write({
                        'image_1920': values['photo']
                    })

Regards