Index: src/services/ThumbnailService.js
===================================================================
--- src/services/ThumbnailService.js	(revision 201ec066b5b266989539a48a81d460335a03ab6d)
+++ src/services/ThumbnailService.js	(revision 492fc204b05b272676483f357af4e0478fc8e01b)
@@ -23,6 +23,7 @@
 const execFileP = promisify(execFile);
 
-// Allowed widths (whitelist → no arbitrary-size abuse). 128 = avatars; 480 ≈ 2× a grid tile.
-export const THUMB_SIZES = new Set([128, 320, 480, 640]);
+// Allowed widths (whitelist → no arbitrary-size abuse). 128 = avatars; 256 ≈ 2× a list
+// cover; 480 ≈ 2× a grid tile. Keep these ~2× the display size so line-art stays crisp.
+export const THUMB_SIZES = new Set([128, 256, 320, 480, 640]);
 
 let _seq = 0;