diff --git a/data_visualization/js/ui.js b/data_visualization/js/ui.js
new file mode 100644
index 0000000..c451e02
--- /dev/null
+++ b/data_visualization/js/ui.js
@@ -0,0 +1,152 @@
+/* UI Logic for temperature and image rendering */
+
+/**
+ * Render a temperature line chart in the #temperature-chart container.
+ * @param {Array<{timestamp: string, value: number}>} temperatures
+ */
+export function renderChart(temperatures) {
+  const container = document.querySelector('#temperature-chart');
+  if (!container) return;
+  container.innerHTML = '';
+
+  const canvas = document.createElement('canvas');
+  canvas.setAttribute('role', 'img');
+  canvas.setAttribute('aria-label', 'Temperaturverlauf');
+  canvas.width = container.clientWidth;
+  canvas.height = 200;
+  container.appendChild(canvas);
+
+  const ctx = canvas.getContext('2d');
+  if (!ctx || temperatures.length === 0) return;
+
+  const values = temperatures.map(t => t.value);
+  const minVal = Math.min(...values);
+  const maxVal = Math.max(...values);
+  const range = maxVal - minVal || 1;
+
+  ctx.strokeStyle = '#2196f3';
+  ctx.lineWidth = 2;
+  ctx.beginPath();
+
+  temperatures.forEach((t, i) => {
+    const x = (i / (temperatures.length - 1)) * canvas.width;
+    const y = canvas.height - ((t.value - minVal) / range) * canvas.height;
+    if (i === 0) {
+      ctx.moveTo(x, y);
+    } else {
+      ctx.lineTo(x, y);
+    }
+  });
+  ctx.stroke();
+}
+
+/**
+ * Render an interactive image gallery.
+ * @param {Array<{filename: string, timestamp: string, metadata?: object}>} images
+ */
+export function renderGallery(images) {
+  const container = document.querySelector('#image-gallery');
+  if (!container) return;
+  container.innerHTML = '';
+
+  const galleryGrid = document.createElement('div');
+  galleryGrid.classList.add('gallery-grid');
+
+  images.forEach((imgData, index) => {
+    const imgEl = document.createElement('div');
+    imgEl.classList.add('gallery-item');
+    imgEl.tabIndex = 0;
+    imgEl.setAttribute('role', 'button');
+    imgEl.setAttribute('aria-label', `Bild ${index + 1}`);
+    imgEl.style.backgroundColor = '#e0e0e0';
+    imgEl.style.display = 'flex';
+    imgEl.style.alignItems = 'center';
+    imgEl.style.justifyContent = 'center';
+    imgEl.style.height = '100px';
+    imgEl.textContent = `Bild ${index + 1}`;
+
+    imgEl.addEventListener('click', () => openImageModal(imgData));
+    imgEl.addEventListener('keypress', e => {
+      if (e.key === 'Enter' || e.key === ' ') {
+        openImageModal(imgData);
+      }
+    });
+
+    galleryGrid.appendChild(imgEl);
+  });
+
+  container.appendChild(galleryGrid);
+}
+
+/**
+ * Display a modal view for a selected image (textual substitute, no actual image).
+ * @param {{filename: string, timestamp: string, metadata?: object}} imgData
+ */
+function openImageModal(imgData) {
+  let modal = document.querySelector('#image-modal');
+  if (!modal) {
+    modal = document.createElement('div');
+    modal.id = 'image-modal';
+    modal.setAttribute('role', 'dialog');
+    modal.setAttribute('aria-modal', 'true');
+    modal.style.position = 'fixed';
+    modal.style.top = 0;
+    modal.style.left = 0;
+    modal.style.right = 0;
+    modal.style.bottom = 0;
+    modal.style.background = 'rgba(0,0,0,0.8)';
+    modal.style.color = '#fff';
+    modal.style.display = 'flex';
+    modal.style.alignItems = 'center';
+    modal.style.justifyContent = 'center';
+
+    const content = document.createElement('div');
+    content.classList.add('modal-content');
+    content.style.padding = '1rem';
+    content.style.background = '#111';
+    content.style.maxWidth = '90%';
+    content.style.textAlign = 'center';
+
+    const closeBtn = document.createElement('button');
+    closeBtn.textContent = 'Schließen';
+    closeBtn.style.marginTop = '1rem';
+    closeBtn.addEventListener('click', () => {
+      modal.remove();
+    });
+
+    modal.appendChild(content);
+    content.appendChild(closeBtn);
+    document.body.appendChild(modal);
+  }
+
+  const content = modal.querySelector('.modal-content');
+  if (content) {
+    content.innerHTML = `<h2>Bild: ${imgData.filename}</h2><p>Aufgenommen: ${imgData.timestamp}</p>`;
+    const closeBtn = document.createElement('button');
+    closeBtn.textContent = 'Schließen';
+    closeBtn.style.marginTop = '1rem';
+    closeBtn.addEventListener('click', () => modal.remove());
+    content.appendChild(closeBtn);
+  }
+}
+
+/**
+ * Update summary statistics for displayed data.
+ * @param {Array<{timestamp: string, value: number}>} temperatures
+ * @param {Array<{filename: string, timestamp: string}>} images
+ */
+export function updateStats(temperatures, images) {
+  const container = document.querySelector('#summary-stats');
+  if (!container) return;
+  container.innerHTML = '';
+
+  const avgTemp =
+    temperatures.length > 0
+      ? (temperatures.reduce((sum, t) => sum + t.value, 0) / temperatures.length).toFixed(2)
+      : 'N/A';
+
+  const imgCount = images.length;
+
+  const statsText = `Durchschnittstemperatur: ${avgTemp}°C | Bilder: ${imgCount}`;
+  container.textContent = statsText;
+}