diff --git a/harnesses/gtauri/frontend/dist/index.html b/harnesses/gtauri/frontend/dist/index.html
index b2d75fb..48fcd3b 100644
--- a/harnesses/gtauri/frontend/dist/index.html
+++ b/harnesses/gtauri/frontend/dist/index.html
@@ -368,6 +368,12 @@ function fitScale() {
   return Math.min(innerWidth / base.w, innerHeight / base.h);
 }
 
+/// P = the element showing the current image, S = the swipe-preview
+/// element. A commit PROMOTES S (it already shows the incoming image
+/// at its own size) and demotes P — the elements swap roles, so no
+/// src copy / re-decode / re-layout ever happens on a swipe.
+let P = vimg, S = vimg2;
+
 function vApply() {
   // Clamp: never zoom out past fit; pan limited to image edges — no
   // blank space around the image, letterboxed axes stay centered.
@@ -377,44 +383,44 @@ function vApply() {
   const my = Math.max(0, (base.h * vScale - innerHeight) / 2);
   if (vTx > mx) vTx = mx; else if (vTx < -mx) vTx = -mx;
   if (vTy > my) vTy = my; else if (vTy < -my) vTy = -my;
-  vimg.style.transform =
+  P.style.transform =
     "translate(" + (vTx - base.w * vScale / 2) + "px," + (vTy - base.h * vScale / 2) + "px) scale(" + vScale + ")";
 }
 
 let viewerId = null, vFullTimer = null, vFullDone = false, vFullSeq = 0;
 
 /* Live swipe preview: while a horizontal drag is in flight at fit
-   scale, the picture being swiped IN renders on the page strip
-   (vimg2) and follows the finger — no blank side. Its grid thumb is
-   a mem hit (~1 ms) in the common case (the grid already requested
-   its neighbors' thumbs). */
+   scale, the picture being swiped IN renders on the page strip (S)
+   and follows the finger — no blank side. Its grid thumb is a mem
+   hit (~1 ms) in the common case (the grid already requested its
+   neighbors' thumbs). */
 let nav = null; // {id, dir(+1 = right/next, -1 = left/prev), w, h, scale, ready}
 function navSet(id, dir) {
   if (nav && nav.id === id) return;
   navHide();
   if (id == null) return;
   nav = { id, dir, w: 0, h: 0, scale: 1, ready: false };
-  vimg2.style.visibility = "hidden";
-  vimg2.onload = () => {
-    if (!nav || nav.id !== id || vimg2.naturalWidth <= 2) return;
-    nav.w = vimg2.naturalWidth; nav.h = vimg2.naturalHeight;
+  S.style.visibility = "hidden";
+  S.onload = () => {
+    if (!nav || nav.id !== id || S.naturalWidth <= 2) return;
+    nav.w = S.naturalWidth; nav.h = S.naturalHeight;
     nav.scale = Math.min(innerWidth / nav.w, innerHeight / nav.h);
     nav.ready = true;
-    vimg2.style.width = nav.w + "px";
-    vimg2.style.height = nav.h + "px";
-    vimg2.style.visibility = "visible";
+    S.style.width = nav.w + "px";
+    S.style.height = nav.h + "px";
+    S.style.visibility = "visible";
     navLayout();
   };
-  vimg2.src = "http://gallery.localhost/thumb/" + id;
+  S.src = "http://gallery.localhost/thumb/" + id;
 }
 function navHide() {
   nav = null;
-  vimg2.style.visibility = "hidden";
+  S.style.visibility = "hidden";
 }
 function navLayout() {
   if (!nav || !nav.ready) return;
   const s = nav.scale;
-  vimg2.style.transform =
+  S.style.transform =
     "translate(" + (vTx + nav.dir * innerWidth - nav.w * s / 2) + "px," +
     (0 - nav.h * s / 2) + "px) scale(" + s + ")";
 }
@@ -422,9 +428,9 @@ function navLayout() {
 function fitViewer(w, h) {
   base.w = w; base.h = h;
   vScale = Math.min(innerWidth / w, innerHeight / h);
-  vimg.style.width = w + "px";
-  vimg.style.height = h + "px";
-  vimg.style.visibility = "visible";
+  P.style.width = w + "px";
+  P.style.height = h + "px";
+  P.style.visibility = "visible";
   vload.textContent = "";
   if (tween) return; // a settle/commit animation owns the transform
   vApply();
@@ -437,7 +443,9 @@ function tryShow(id, url, isFull) {
   im.addEventListener("load", () => {
     if (viewerId !== id) return;
     if (im.naturalWidth <= 2) return;
-    vimg.src = im.src;
+    if (isFull && tween) return; // a slide owns base/vScale right now;
+                                 // the safety timer re-requests shortly
+    P.src = im.src;
     fitViewer(im.naturalWidth, im.naturalHeight);
     if (isFull) {
       vFullDone = true;
@@ -448,20 +456,21 @@ function tryShow(id, url, isFull) {
 }
 
 /// openViewer(id, keepVisible): keepVisible = the image was promoted
-/// by a swipe commit — vimg ALREADY shows its thumbnail, so don't
-/// hide it or re-request the thumb (only full-res is wanted).
+/// by a swipe commit — P ALREADY shows its thumbnail at the right
+/// scale/position (finishCommit set it), so don't reset the view or
+/// re-request the thumb (only full-res is wanted).
 function openViewer(id, keepVisible) {
   viewerId = id;
   if (!keepVisible) navHide();
   vFullDone = false;
   vFullSeq = 0;
-  vScale = 1; vTx = 0; vTy = 0;
   if (keepVisible) {
-    vimg.style.visibility = "visible";
+    P.style.visibility = "visible";
     vload.textContent = "";
   } else {
+    vScale = 1; vTx = 0; vTy = 0;
     vload.textContent = "loading…";
-    vimg.style.visibility = "hidden";
+    P.style.visibility = "hidden";
     // 1) INSTANT: the grid thumb (Rust mem cache, ~1 ms).
     tryShow(id, "http://gallery.localhost/thumb/" + id, false);
   }
@@ -477,7 +486,7 @@ function openViewer(id, keepVisible) {
     }
     if (++vFullSeq > 10) {
       if (vFullTimer) { clearInterval(vFullTimer); vFullTimer = null; }
-      if (viewerId === id && vimg.naturalWidth <= 2) {
+      if (viewerId === id && P.naturalWidth <= 2) {
         vload.textContent = "image unavailable";
       }
       return;
@@ -493,7 +502,8 @@ function closeViewer() {
   navHide();
   if (vFullTimer) { clearInterval(vFullTimer); vFullTimer = null; }
   viewer.classList.remove("open");
-  vimg.src = "";
+  P.src = "";
+  S.src = ""; // release any parked full-res bitmap
 }
 document.getElementById("vclose").addEventListener("click", closeViewer);
 addEventListener("keydown", (e) => {
@@ -520,7 +530,7 @@ function atFit() {
 
 /// Raw transform write (no clamping) — used by the tween and swipes.
 function applyTransform() {
-  vimg.style.transform =
+  P.style.transform =
     "translate(" + (vTx - base.w * vScale / 2) + "px," + (vTy - base.h * vScale / 2) + "px) scale(" + vScale + ")";
 }
 
@@ -595,28 +605,29 @@ function commitTo(ni, delta, vel) {
   tween = { raf: requestAnimationFrame(step), commit: true, target: ni };
 }
 
-/// Swap the elements' roles at the settled positions: vimg2 (the
-/// incoming image) becomes primary at 0 with its own dimensions (see
-/// the aspect note there), vimg shows it next paint, the old image is
-/// gone. Called when the commit tween completes AND on mid-flight
-/// takeover — a new touch/key during a commit finishes it instantly
-/// so the new gesture acts on the landed image (swipes chain).
+/// Settle the commit and swap the elements' roles. S (the preview)
+/// ALREADY shows the incoming image at its own size and scale — it
+/// is promoted to primary in place (moved to 0, brought to front),
+/// and the old primary is hidden immediately. No src copy, no async
+/// paint, no re-layout: the promoted pixels were on screen the whole
+/// drag, so the settled frame is the drag frame — no size jump.
+/// Called when the commit tween completes AND on mid-flight takeover
+/// (a touch/key during a commit finishes it instantly so the new
+/// gesture acts on the landed image — swipes chain).
 function finishCommit(ni) {
   const id = ids[ni];
   if (nav && nav.id === id && nav.ready) {
-    const nw = nav.w, nh = nav.h, ns = nav.scale;
-    vimg.src = vimg2.src; // cached + decoded → paints immediately
-    base.w = nw; base.h = nh;
-    vScale = ns;
-    vimg.style.width = nw + "px";
-    vimg.style.height = nh + "px";
+    base.w = nav.w; base.h = nav.h;
+    vScale = nav.scale;
     vTx = 0; vTy = 0;
+    P.onload = null; S.onload = null; // stale preview/commit handlers
+    P.style.visibility = "hidden";    // park the outgoing image
+    viewer.insertBefore(S, P);        // promoted element goes in front
+    [P, S] = [S, P];
     applyTransform();
     openViewer(id, true);
-    // Hide the preview only once the primary has the bytes.
-    vimg.onload = () => { if (viewerId === id) navHide(); };
   } else {
-    // Preview never made it (keyboard nav / slow thumb): plain open —
+    // Preview never loaded (keyboard nav / slow thumb): plain open —
     // the thumb round-trip sets the right dimensions.
     openViewer(id, false);
   }