Represent tracing media as symbols and add pool thumbnails

clips/models.py

@@ -70,6 +70,21 @@ class Sound(models.Model):
     created = models.DateTimeField(auto_now_add=True)
 
 
+class Image(models.Model):
+    """An uploaded still — a drawing, a photo, a model sheet — kept as uploaded, to
+    be traced over. Never part of the picture: a document names its blob as a
+    tracing symbol's `:media`, and the page draws it over the stage."""
+
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    blob = models.ForeignKey(Blob, on_delete=models.PROTECT, related_name="image_for")
+    filename = models.CharField(max_length=255)
+    label = models.CharField(max_length=200, blank=True,
+                             help_text="what a person called it; the filename when empty")
+    width = models.PositiveIntegerField(help_text="pixels, as ffprobe reports them")
+    height = models.PositiveIntegerField()
+    created = models.DateTimeField(auto_now_add=True)
+
+
 class Extraction(models.Model):
     """One requested decode of a source into immutable footage."""
 
@@ -235,7 +250,7 @@ class Project(models.Model):
         settings.AUTH_USER_MODEL, blank=True, related_name="shared_projects",
     )
     name = models.CharField(max_length=200, default="untitled")
-    schema_version = models.PositiveIntegerField(default=5)
+    schema_version = models.PositiveIntegerField(default=6)
     seq = models.PositiveBigIntegerField(default=0)
     palette = models.CharField(max_length=64, default="arthur/default")
     created = models.DateTimeField(auto_now_add=True)