skip image optimization for tiny placeholder images

Images under 100 bytes (e.g. 44-byte 1x1 pixel webp stubs from seeded
data) crash libvips. Filter them at three levels: VariantCache skips
them in the query, Optimizer returns :too_small, and OptimizeWorker
cancels (not retries) the job to avoid activity log spam.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

lib/berrypod/images/optimize_worker.ex

@@ -29,6 +29,7 @@ defmodule Berrypod.Images.OptimizeWorker do
       {:ok, _} -> :ok
       {:error, :not_found} -> {:cancel, :image_not_found}
       {:error, :no_data} -> {:cancel, :no_image_data}
+      {:error, :too_small} -> {:cancel, :image_too_small}
       {:error, reason} -> {:error, reason}
     end
   end

lib/berrypod/images/optimizer.ex

@@ -13,6 +13,8 @@ defmodule Berrypod.Images.Optimizer do
   @thumb_size 200
   @max_stored_width 2000
   @storage_quality 90
+  # Skip images smaller than this — they're placeholders or corrupt
+  @min_image_bytes 100
 
   def cache_dir do
     Application.get_env(:berrypod, :image_cache_dir) ||
@@ -80,6 +82,9 @@ defmodule Berrypod.Images.Optimizer do
         Repo.update!(ImageSchema.changeset(image, %{variants_status: "complete"}))
         {:ok, :svg_skipped}
 
+      %{data: data} when byte_size(data) < @min_image_bytes ->
+        {:error, :too_small}
+
       %{data: data, source_width: width} = image ->
         File.mkdir_p!(cache_dir())
 

lib/berrypod/images/variant_cache.ex

@@ -52,10 +52,12 @@ defmodule Berrypod.Images.VariantCache do
 
   defp ensure_database_image_variants do
     # Only load IDs and source_width for the disk check — avoids loading BLOBs
+    # Skip tiny images (< 100 bytes) — they're placeholders that can't be processed
     incomplete_ids =
       ImageSchema
       |> where([i], i.variants_status != "complete" or is_nil(i.variants_status))
       |> where([i], i.is_svg == false)
+      |> where([i], i.file_size >= 100)
       |> select([i], {i.id, i.source_width})
       |> Repo.all()