diff --git a/internal/restorable/image.go b/internal/restorable/image.go
index 7a8511dc5..2ca993ab0 100644
--- a/internal/restorable/image.go
+++ b/internal/restorable/image.go
@@ -267,6 +267,7 @@ func (i *Image) makeStale(rect image.Rectangle) {
 		return
 	}
 
+	origNum := len(i.staleRegions)
 	i.staleRegions = i.appendRegionsForDrawTriangles(i.staleRegions)
 	if !rect.Empty() {
 		i.staleRegions = append(i.staleRegions, rect)
@@ -274,6 +275,11 @@ func (i *Image) makeStale(rect image.Rectangle) {
 
 	i.clearDrawTrianglesHistory()
 
+	// Clear pixels to save memory.
+	for _, r := range i.staleRegions[origNum:] {
+		i.basePixels.Clear(r.Min.X, r.Min.Y, r.Dx(), r.Dy())
+	}
+
 	// Don't have to call makeStale recursively here.
 	// Restoring is done after topological sorting is done.
 	// If an image depends on another stale image, this means that