diff --git a/core/dr-catalog/examples/catalog_bench.rs b/core/dr-catalog/examples/catalog_bench.rs
index f5227f7..3f94f21 100644
--- a/core/dr-catalog/examples/catalog_bench.rs
+++ b/core/dr-catalog/examples/catalog_bench.rs
@@ -155,8 +155,8 @@ fn local_original_count(conn: &rusqlite::Connection) -> i64 {
     conn.query_row(
         "SELECT count(*) FROM images i
           WHERE i.shadowed_by IS NULL AND i.trashed_at IS NULL
-            AND EXISTS (SELECT 1 FROM image_cache ic
-                         WHERE ic.image_id = i.id AND ic.tier_actual >= 2)",
+            AND i.id IN (SELECT ic.image_id FROM image_cache ic
+                          WHERE ic.tier_actual >= 2)",
         [],
         |r| r.get(0),
     )
diff --git a/ui/dr-ui/src/library/spans.rs b/ui/dr-ui/src/library/spans.rs
index 08e70df..c6e2aac 100644
--- a/ui/dr-ui/src/library/spans.rs
+++ b/ui/dr-ui/src/library/spans.rs
@@ -364,13 +364,21 @@ pub(super) fn total_images_filtered(
 /// Whole-library, like the star counts beside it: the chip says what narrowing
 /// to it would show, so counting only the current window would make it
 /// describe the view it exists to change.
+///
+/// Driven from `image_cache`, which holds a row only for what has been
+/// fetched: an `IN` list the planner walks, probing `images` by id for each.
+/// Spelled as a correlated `EXISTS` it walked every visible image and
+/// probed the cache for each -- 19,000 probes to find 254 originals on the
+/// reference library, 2 ms paid on every star keystroke beside the rating
+/// counts. `image_id` is the cache's key, so the list holds each image once
+/// and the count is the one the `EXISTS` gave.
 pub fn local_original_count(catalog: &Catalog) -> Result<usize, dr_catalog::CatalogError> {
     let n: i64 = catalog.connection().query_row(
         &format!(
             "SELECT count(*) FROM images i
               WHERE {VISIBLE}
-                AND EXISTS (SELECT 1 FROM image_cache ic
-                             WHERE ic.image_id = i.id AND ic.tier_actual >= {})",
+                AND i.id IN (SELECT ic.image_id FROM image_cache ic
+                              WHERE ic.tier_actual >= {})",
             dr_types::Tier::Original.stored()
         ),
         [],