Django how to get in model the value from another model

Question

How to get in django models class Another value of BlogPageGalleryImage image or foreign key or parental key?

class BlogPage(Page):
    date = models.DateField("Дата публикации" , default=datetime.date.today  )
    body = RichTextField(blank=True)
    name = models.CharField(max_length=80, default='Лучший')



class BlogPageGalleryImage(Orderable):
    page = ParentalKey(BlogPage, related_name='gallery_images')
    image = models.ForeignKey('wagtailimages.Image', on_delete=models.CASCADE, related_name='+')
    caption = models.CharField(blank=True, max_length=250)
    panels = [
        ImageChooserPanel('image'),
        FieldPanel('caption'),
    ]

class Another(BlogPage):
    page = ParentalKey(BlogPage, related_name='instagram_post')
    Image = BlogPageGalleryImage.objects.get(BlogPageGalleryImage.) 
    caption = models.CharField(blank=True, max_length=250)
    panels = [
        ImageChooserPanel('image'),
        FieldPanel('caption'),
    ]  

Answer 1

It seems you are looking to access the blog page images in your BlogPage and Another template. This can be achieved by adding the blog page images to the rendering context. To do this override the get_context in BlogPage method:

def get_context(self, request, *args, **kwargs):
    context = super(BlogPage, self).get_context(
       request, *args, **kwargs
    )
    context['images'] = BlogPageGalleryImage.objects.filter(
        page=self,
    )
    return context

This means that you can now in your template access the images using {{ images }} . So for example:

{% for i in images %}
    <div class="image">
        {% image i.image %}
        <p>{{ i.caption }}</p>
    </div>
{% endfor %}