diff --git a/copyparty/__main__.py b/copyparty/__main__.py
index 9b8a86e7..f88c5cc1 100755
--- a/copyparty/__main__.py
+++ b/copyparty/__main__.py
@@ -874,7 +874,7 @@ def add_thumbnail(ap):
     ap2.add_argument("--th-poke", metavar="SEC", type=int, default=300, help="activity labeling cooldown -- avoids doing keepalive pokes (updating the mtime) on thumbnail folders more often than SEC seconds")
     ap2.add_argument("--th-clean", metavar="SEC", type=int, default=43200, help="cleanup interval; 0=disabled")
     ap2.add_argument("--th-maxage", metavar="SEC", type=int, default=604800, help="max folder age -- folders which haven't been poked for longer than --th-poke seconds will get deleted every --th-clean seconds")
-    ap2.add_argument("--th-covers", metavar="N,N", type=u, default="folder.png,folder.jpg,cover.png,cover.jpg", help="folder thumbnails to stat/look for")
+    ap2.add_argument("--th-covers", metavar="N,N", type=u, default="folder.png,folder.jpg,cover.png,cover.jpg", help="folder thumbnails to stat/look for; case-insensitive if -e2d")
     # https://pillow.readthedocs.io/en/stable/handbook/image-file-formats.html
     # https://github.com/libvips/libvips
     # ffmpeg -hide_banner -demuxers | awk '/^ D  /{print$2}' | while IFS= read -r x; do ffmpeg -hide_banner -h demuxer=$x; done | grep -E '^Demuxer |extensions:'
diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index 749d66fe..3316d110 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -3248,6 +3248,9 @@ class HttpCli(object):
         ):
             raise Pebkac(403)
 
+        e2d = "e2d" in vn.flags
+        e2t = "e2t" in vn.flags
+
         self.html_head = vn.flags.get("html_head", "")
         if vn.flags.get("norobots") or "b" in self.uparam:
             self.out_headers["X-Robots-Tag"] = "noindex, nofollow"
@@ -3255,16 +3258,37 @@ class HttpCli(object):
             self.out_headers.pop("X-Robots-Tag", None)
 
         is_dir = stat.S_ISDIR(st.st_mode)
+        icur = None
+        if e2t or (e2d and is_dir):
+            idx = self.conn.get_u2idx()
+            icur = idx.get_cur(dbv.realpath)
+
         if self.can_read:
             th_fmt = self.uparam.get("th")
             if th_fmt is not None:
                 if is_dir:
-                    for fn in self.args.th_covers.split(","):
-                        fp = os.path.join(abspath, fn)
-                        if bos.path.exists(fp):
-                            vrem = "{}/{}".format(vrem.rstrip("/"), fn).strip("/")
-                            is_dir = False
-                            break
+                    vrem = vrem.rstrip("/")
+                    if icur and vrem:
+                        q = "select fn from cv where rd=? and dn=?"
+                        crd, cdn = vrem.rsplit("/", 1) if "/" in vrem else ("", vrem)
+                        # no mojibake support:
+                        try:
+                            cfn = icur.execute(q, (crd, cdn)).fetchone()
+                            if cfn:
+                                fn = cfn[0]
+                                fp = os.path.join(abspath, fn)
+                                if bos.path.exists(fp):
+                                    vrem = "{}/{}".format(vrem, fn).strip("/")
+                                    is_dir = False
+                        except:
+                            pass
+                    else:
+                        for fn in self.args.th_covers:
+                            fp = os.path.join(abspath, fn)
+                            if bos.path.exists(fp):
+                                vrem = "{}/{}".format(vrem, fn).strip("/")
+                                is_dir = False
+                                break
 
                     if is_dir:
                         return self.tx_ico("a.folder")
@@ -3371,8 +3395,8 @@ class HttpCli(object):
             "taglist": [],
             "srvinf": srv_infot,
             "acct": self.uname,
-            "idx": ("e2d" in vn.flags),
-            "itag": ("e2t" in vn.flags),
+            "idx": e2d,
+            "itag": e2t,
             "lifetime": vn.flags.get("lifetime") or 0,
             "frand": bool(vn.flags.get("rand")),
             "perms": perms,
@@ -3391,8 +3415,8 @@ class HttpCli(object):
             "taglist": [],
             "def_hcols": [],
             "have_emp": self.args.emp,
-            "have_up2k_idx": ("e2d" in vn.flags),
-            "have_tags_idx": ("e2t" in vn.flags),
+            "have_up2k_idx": e2d,
+            "have_tags_idx": e2t,
             "have_acode": (not self.args.no_acode),
             "have_mv": (not self.args.no_mv),
             "have_del": (not self.args.no_del),
@@ -3468,11 +3492,6 @@ class HttpCli(object):
         if not self.args.ed or "dots" not in self.uparam:
             ls_names = exclude_dotfiles(ls_names)
 
-        icur = None
-        if "e2t" in vn.flags:
-            idx = self.conn.get_u2idx()
-            icur = idx.get_cur(dbv.realpath)
-
         add_fk = vn.flags.get("fk")
 
         dirs = []
diff --git a/copyparty/svchub.py b/copyparty/svchub.py
index a8bcf5b7..0557707b 100644
--- a/copyparty/svchub.py
+++ b/copyparty/svchub.py
@@ -348,6 +348,8 @@ class SvcHub(object):
         if al.rsp_jtr:
             al.rsp_slp = 0.000001
 
+        al.th_covers = set(al.th_covers.split(","))
+
         return True
 
     def _setlimits(self) -> None:
diff --git a/copyparty/up2k.py b/copyparty/up2k.py
index 6ca22781..16bf6028 100644
--- a/copyparty/up2k.py
+++ b/copyparty/up2k.py
@@ -73,6 +73,9 @@ if True:  # pylint: disable=using-constant-test
 if TYPE_CHECKING:
     from .svchub import SvcHub
 
+zs = "avif,avifs,bmp,gif,heic,heics,heif,heifs,ico,j2p,j2k,jp2,jpeg,jpg,jpx,png,tga,tif,tiff,webp"
+CV_EXTS = set(zs.split(","))
+
 
 class Dbw(object):
     def __init__(self, c: "sqlite3.Cursor", n: int, t: float) -> None:
@@ -945,6 +948,7 @@ class Up2k(object):
         unreg: list[str] = []
         files: list[tuple[int, int, str]] = []
         fat32 = True
+        cv = ""
 
         assert self.pp and self.mem_cur
         self.pp.msg = "a{} {}".format(self.pp.n, cdir)
@@ -1007,6 +1011,12 @@ class Up2k(object):
                     continue
 
                 files.append((sz, lmod, iname))
+                liname = iname.lower()
+                if sz and (
+                    iname in self.args.th_covers
+                    or (not cv and liname.rsplit(".", 1)[-1] in CV_EXTS)
+                ):
+                    cv = iname
 
         # folder of 1000 files = ~1 MiB RAM best-case (tiny filenames);
         # free up stuff we're done with before dhashing
@@ -1019,6 +1029,7 @@ class Up2k(object):
                 zh = hashlib.sha1()
                 _ = [zh.update(str(x).encode("utf-8", "replace")) for x in files]
 
+            zh.update(cv.encode("utf-8", "replace"))
             zh.update(spack(b"<d", cst.st_mtime))
             dhash = base64.urlsafe_b64encode(zh.digest()[:12]).decode("ascii")
             sql = "select d from dh where d = ? and h = ?"
@@ -1032,6 +1043,18 @@ class Up2k(object):
             if c.fetchone():
                 return ret
 
+        if cv and rd:
+            # mojibake not supported (for performance / simplicity):
+            try:
+                q = "select * from cv where rd=? and dn=? and +fn=?"
+                crd, cdn = rd.rsplit("/", 1) if "/" in rd else ("", rd)
+                if not db.c.execute(q, (crd, cdn, cv)).fetchone():
+                    db.c.execute("delete from cv where rd=? and dn=?", (crd, cdn))
+                    db.c.execute("insert into cv values (?,?,?)", (crd, cdn, cv))
+                    db.n += 1
+            except Exception as ex:
+                self.log("cover {}/{} failed: {}".format(rd, cv, ex), 6)
+
         seen_files = set([x[2] for x in files])  # for dropcheck
         for sz, lmod, fn in files:
             if self.stop:
@@ -1228,6 +1251,18 @@ class Up2k(object):
         if n_rm2:
             self.log("forgetting {} shadowed deleted files".format(n_rm2))
 
+        # then covers
+        n_rm3 = 0
+        q = "delete from cv where rd=? and dn=? and +fn=?"
+        for crd, cdn, fn in cur.execute("select * from cv"):
+            ap = os.path.join(top, crd, cdn, fn)
+            if not bos.path.exists(ap):
+                c2.execute(q, (crd, cdn, fn))
+                n_rm3 += 1
+
+        if n_rm3:
+            self.log("forgetting {} deleted covers".format(n_rm3))
+
         c2.close()
         return n_rm + n_rm2
 
@@ -1380,6 +1415,7 @@ class Up2k(object):
             cur, _ = reg
             self._set_tagscan(cur, True)
             cur.execute("delete from dh")
+            cur.execute("delete from cv")
             cur.connection.commit()
 
     def _set_tagscan(self, cur: "sqlite3.Cursor", need: bool) -> bool:
@@ -1960,6 +1996,7 @@ class Up2k(object):
 
         if ver == DB_VER:
             try:
+                self._add_cv_tab(cur)
                 self._add_xiu_tab(cur)
                 self._add_dhash_tab(cur)
             except:
@@ -2055,6 +2092,7 @@ class Up2k(object):
 
         self._add_dhash_tab(cur)
         self._add_xiu_tab(cur)
+        self._add_cv_tab(cur)
         self.log("created DB at {}".format(db_path))
         return cur
 
@@ -2103,6 +2141,27 @@ class Up2k(object):
 
         cur.connection.commit()
 
+    def _add_cv_tab(self, cur: "sqlite3.Cursor") -> None:
+        # v5b -> v5c
+        try:
+            cur.execute("select rd, dn, fn from cv limit 1").fetchone()
+            return
+        except:
+            pass
+
+        for cmd in [
+            r"create table cv (rd text, dn text, fn text)",
+            r"create index cv_i on cv(rd, dn)",
+        ]:
+            cur.execute(cmd)
+
+        try:
+            cur.execute("delete from dh")
+        except:
+            pass
+
+        cur.connection.commit()
+
     def _job_volchk(self, cj: dict[str, Any]) -> None:
         if not self.register_vpath(cj["ptop"], cj["vcfg"]):
             if cj["ptop"] not in self.registry:
@@ -2824,6 +2883,16 @@ class Up2k(object):
                 with self.rescan_cond:
                     self.rescan_cond.notify_all()
 
+        if rd and sz and fn.lower() in self.args.th_covers:
+            # wasteful; db_add will re-index actual covers
+            # but that won't catch existing files
+            crd, cdn = rd.rsplit("/", 1) if "/" in rd else ("", rd)
+            try:
+                db.execute("delete from cv where rd=? and dn=?", (crd, cdn))
+                db.execute("insert into cv values (?,?,?)", (crd, cdn, fn))
+            except:
+                pass
+
     def handle_rm(self, uname: str, ip: str, vpaths: list[str], lim: list[int]) -> str:
         n_files = 0
         ok = {}
diff --git a/copyparty/web/browser.css b/copyparty/web/browser.css
index 5bbec98f..16bc0c2b 100644
--- a/copyparty/web/browser.css
+++ b/copyparty/web/browser.css
@@ -93,6 +93,7 @@
 	--g-fsel-bg: #d39;
 	--g-fsel-b1: #f4a;
 	--g-fsel-ts: #804;
+	--g-dfg: var(--srv-3);
 	--g-fg: var(--a-hil);
 	--g-bg: var(--bg-u2);
 	--g-b1: var(--bg-u4);
@@ -327,6 +328,7 @@ html.c {
 }
 html.cz {
 	--bgg: var(--bg-u2);
+	--srv-3: #fff;
 }
 html.cy {
 	--fg: #fff;
@@ -354,6 +356,7 @@ html.cy {
 	--chk-fg: #fd0;
 
 	--srv-1: #f00;
+	--srv-3: #fff;
 	--op-aa-bg: #fff;
 
 	--u2-b1-bg: #f00;
@@ -964,6 +967,9 @@ html.y #path a:hover {
 #ggrid>a.dir:before {
 	content: '📂';
 }
+#ggrid>a.dir>span {
+	color: var(--g-dfg);
+}
 #ggrid>a.au:before {
 	content: '💾';
 }
@@ -1010,6 +1016,9 @@ html.np_open #ggrid>a.au:before {
 	background: var(--g-sel-bg);
 	border-color: var(--g-sel-b1);
 }
+#ggrid>a.sel>span {
+	color: var(--g-sel-fg);
+}
 #ggrid>a.sel,
 #ggrid>a[tt].sel {
 	border-top: 1px solid var(--g-fsel-b1);