determine signature image

signature_image2.py

    def signature_image2(self):
        # image or attachment
        if self.image:
            if self.image.height == self.image.width or self.image.size <= 50000: # legacy pre-cropped, pre-sized square image, smaller than about 50KB
                if self.image_attachments():
                    attachments = sorted(self.image_attachments(), key=lambda x: x.file.size, reverse=True)

                    for attachment in attachments:
                        if attachment.selected:
                            return attachment.file

                    # get biggest attachment
                    return attachments[0].file
            else: # non-legacy image
                return self.image
        else:
            # redundant for now...
            if self.image_attachments():
                attachments = sorted(self.image_attachments(), key=lambda x: x.file.size, reverse=True)

                for attachment in attachments:
                    if attachment.selected:
                        return attachment.file

                # get biggest attachment
                return attachments[0].file

        # series
        if self.series and self.series.image:
            return self.series.image

        # author
        author_imgs = []

        if self.authors:
            for a in self.get_authors():
                if a.image:
                    author_imgs.append(a.image)
        if author_imgs and author_imgs[0]:
            return author_imgs[0]

        # icon
        return ARTICLE_ICON