diff --git a/internal/web/service/panel/sponsor.go b/internal/web/service/panel/sponsor.go
index 0df1d46db..2e0356ddf 100644
--- a/internal/web/service/panel/sponsor.go
+++ b/internal/web/service/panel/sponsor.go
@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"maps"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -45,6 +46,7 @@ const (
 	sponsorsErrTTL   = 10 * time.Minute
 	maxSponsorsBytes = 256 << 10
 	maxLogoBytes     = 256 << 10
+	maxSponsorLogos  = 32
 	localSponsorsDir = "../sponsors/3X"
 	sponsorLogoPath  = "/sponsors/logo/"
 )
@@ -118,7 +120,7 @@ func (s *PanelService) GetSponsorLogo(name string) ([]byte, string, error) {
 	if err != nil {
 		return nil, "", err
 	}
-	if !slices.ContainsFunc(sponsors.Sponsors, func(sp Sponsor) bool { return sp.Logo == sponsorLogoPath+name }) {
+	if !sponsors.hasLogo(name) {
 		return nil, "", ErrSponsorLogoUnknown
 	}
 	logosMu.Lock()
@@ -138,10 +140,16 @@ func (s *PanelService) GetSponsorLogo(name string) ([]byte, string, error) {
 	default:
 		l = sponsorLogo{err: err, retryAt: now.Add(sponsorsErrTTL)}
 	}
+	// Logos that left the active list go with every store, so the cache never outgrows maxSponsorLogos.
+	maps.DeleteFunc(logos, func(cached string, _ sponsorLogo) bool { return !sponsors.hasLogo(cached) })
 	logos[name] = l
 	return l.data, l.contentType, l.err
 }
 
+func (list *SponsorList) hasLogo(name string) bool {
+	return slices.ContainsFunc(list.Sponsors, func(sp Sponsor) bool { return sp.Logo == sponsorLogoPath+name })
+}
+
 func fetchSponsorLogo(name string) ([]byte, string, error) {
 	data, err := readSponsorSource(sponsorLogoBase+name, filepath.Join(localSponsorsDir, "logos", name), maxLogoBytes)
 	if err != nil {
@@ -216,6 +224,7 @@ func activeSponsors(raw *SponsorList, now time.Time) *SponsorList {
 	if strings.HasPrefix(raw.Contact, "https://") {
 		out.Contact = raw.Contact
 	}
+	logoNames := map[string]bool{}
 	for _, sp := range raw.Sponsors {
 		// A missing enable counts as on, so a forgotten field never hides a paid slot.
 		disabled := sp.Enable != nil && !*sp.Enable
@@ -223,12 +232,6 @@ func activeSponsors(raw *SponsorList, now time.Time) *SponsorList {
 		if disabled || notStarted || sp.ID == "" || !now.Before(sp.Until) || !strings.HasPrefix(sp.Link, "https://") {
 			continue
 		}
-		// A bad logo name drops only the logo; the paid slot still renders with its initial.
-		if sponsorLogoRe.MatchString(sp.Logo) {
-			sp.Logo = sponsorLogoPath + sp.Logo
-		} else {
-			sp.Logo = ""
-		}
 		slots := make([]string, 0, len(sp.Slots))
 		for _, slot := range sp.Slots {
 			if sponsorSlots[slot] {
@@ -238,6 +241,14 @@ func activeSponsors(raw *SponsorList, now time.Time) *SponsorList {
 		if len(slots) == 0 {
 			continue
 		}
+		// A bad or surplus logo name drops only the logo; the paid slot renders with its initial.
+		// Every name kept here becomes one cached image, so the list must not decide how many.
+		if sponsorLogoRe.MatchString(sp.Logo) && (logoNames[sp.Logo] || len(logoNames) < maxSponsorLogos) {
+			logoNames[sp.Logo] = true
+			sp.Logo = sponsorLogoPath + sp.Logo
+		} else {
+			sp.Logo = ""
+		}
 		sp.Slots = slots
 		out.Sponsors = append(out.Sponsors, sp)
 	}
diff --git a/internal/web/service/panel/sponsor_test.go b/internal/web/service/panel/sponsor_test.go
index c6bfe0c6b..212ae5e21 100644
--- a/internal/web/service/panel/sponsor_test.go
+++ b/internal/web/service/panel/sponsor_test.go
@@ -2,6 +2,7 @@ package panel
 
 import (
 	"errors"
+	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -114,6 +115,10 @@ func setupSponsorServer(t *testing.T, body string) *atomic.Int32 {
 			w.WriteHeader(http.StatusBadGateway)
 			return
 		}
+		if strings.HasPrefix(r.URL.Path, "/media/many") {
+			_, _ = w.Write(pngMagic)
+			return
+		}
 		switch r.URL.Path {
 		case "/media/acme.png":
 			_, _ = w.Write(pngMagic)
@@ -234,6 +239,40 @@ func TestGetSponsorLogo(t *testing.T) {
 	}
 }
 
+// The feed decides which logo names exist, so it must not decide how many the panel holds in memory.
+func TestSponsorLogoCacheStaysBounded(t *testing.T) {
+	var list []string
+	for i := range 3 * maxSponsorLogos {
+		until := "2099-01-01T00:00:00Z"
+		if i < maxSponsorLogos {
+			until = sponsorTestNow.Add(time.Minute).Format(time.RFC3339)
+		}
+		list = append(list, fmt.Sprintf(`{"id":"s%d","slots":["page"],"until":%q,
+			"link":"https://s.example/","logo":"many%d.png"}`, i, until, i))
+	}
+	setupSponsorServer(t, `{"sponsors":[`+strings.Join(list, ",")+`]}`)
+	now := sponsorTestNow
+	sponsorNow = func() time.Time { return now }
+	svc := &PanelService{}
+
+	got, err := svc.GetSponsors()
+	if err != nil || len(got.Sponsors) != 3*maxSponsorLogos {
+		t.Fatalf("GetSponsors() = %d sponsors, %v; want all %d kept (only surplus logos drop)", len(got.Sponsors), err, 3*maxSponsorLogos)
+	}
+	for _, step := range []string{"full list", "first sponsors expired"} {
+		served := 0
+		for i := range 3 * maxSponsorLogos {
+			if _, _, err := svc.GetSponsorLogo(fmt.Sprintf("many%d.png", i)); err == nil {
+				served++
+			}
+		}
+		if served != maxSponsorLogos || len(logos) != maxSponsorLogos {
+			t.Errorf("%s: served %d logos, cache holds %d, want %d for both", step, served, len(logos), maxSponsorLogos)
+		}
+		now = now.Add(2 * time.Minute)
+	}
+}
+
 func TestGetSponsorsCachesAndExpiresWhileCached(t *testing.T) {
 	hits := setupSponsorServer(t, `{"sponsors":[{"id":"acme","slots":["page"],
 		"until":"2026-10-15T00:30:00Z","link":"https://acme.example/"}]}`)