a hideous hack to create a wagtail modeladmin view for a custom image class

wagtail_hooks.py

from django.utils.translation import ugettext_lazy as _
from django.utils.safestring import mark_safe
from django.forms.utils import flatatt
from django.shortcuts import redirect

from wagtail.wagtailimages.views.images import edit as image_edit_view
from wagtail.contrib.modeladmin import views


class StandardImageEditViewWrapper(views.EditView):

    def get(self, request):
        response = image_edit_view(request, self.instance_pk)
        # hack the normal form post url so we can get redirected back to this view
        standard_post_url = reverse('wagtailimages:edit', args=[self.instance_pk])
        response.content = response.content.decode('utf8').replace(
            standard_post_url, self.edit_url
        ).encode('utf8')
        return response

    def post(self, request):
        response = image_edit_view(request, self.instance_pk)
        if response.status_code == 302:
            # intercept redirects that would go back to normal image edit
            # and bring them back here
            return redirect(self.get_success_url())





class ImageModelAdmin(ModelAdmin, ThumbnailMixin):
    model = CustomImage
    add_to_settings_menu = False
    list_display = ('admin_thumb', 'title', 'production', 'castmember')
    list_filter = ('production', 'castmember')
    search_fields = ['title']
    menu_label = 'Categorised Images'
    menu_icon = 'image'
    menu_order = 106
    list_per_page = 20

    thumb_image_filter_spec = 'fill-100x100'
    thumb_image_width = 100
    thumb_col_header_text = _('image')

    def admin_thumb(self, obj):
        # hacked version of ThumbnailMixin.admin_thumb but image=obj
        img_attrs = {
            'src': self.thumb_default,
            'width': self.thumb_image_width,
            'class': self.thumb_classname,
        }
        # try to get a rendition of the image to use
        from wagtail.wagtailimages.shortcuts import get_rendition_or_not_found
        spec = self.thumb_image_filter_spec
        rendition = get_rendition_or_not_found(obj, spec)
        img_attrs.update({'src': rendition.url})
        return mark_safe('<img{}>'.format(flatatt(img_attrs)))
    admin_thumb.short_description = thumb_col_header_text

    edit_view_class = StandardImageEditViewWrapper


modeladmin_register(ImageModelAdmin)