diff --git a/src/systems/integration/expressionSync.js b/src/systems/integration/expressionSync.js
index acf7a60..a700687 100644
--- a/src/systems/integration/expressionSync.js
+++ b/src/systems/integration/expressionSync.js
@@ -15,6 +15,7 @@ import {
     removeSyncedExpressionPortrait
 } from '../../core/state.js';
 import { saveChatData } from '../../core/persistence.js';
+import { isSafeImageSrc, normalizeImageSrc, resolveImageUrl } from '../../utils/imageUrls.js';
 import { renderAlternatePresentCharacters } from '../ui/alternatePresentCharacters.js';
 
 let expressionContainerObserver = null;
@@ -33,20 +34,11 @@ function normalizeName(name) {
 }
 
 function normalizeExpressionSrc(src) {
-    return String(src || '').trim();
+    return normalizeImageSrc(src);
 }
 
 function resolveExpressionUrl(src) {
-    const normalized = normalizeExpressionSrc(src);
-    if (!normalized) {
-        return null;
-    }
-
-    try {
-        return new URL(normalized, window.location.href);
-    } catch {
-        return null;
-    }
+    return resolveImageUrl(src);
 }
 
 function isDocumentLikeUrl(src) {
@@ -76,6 +68,10 @@ function isUsableExpressionSrc(src) {
         return false;
     }
 
+    if (!isSafeImageSrc(normalized)) {
+        return false;
+    }
+
     return true;
 }
 
diff --git a/src/systems/ui/alternatePresentCharacters.js b/src/systems/ui/alternatePresentCharacters.js
index 34969ef..e0a28d0 100644
--- a/src/systems/ui/alternatePresentCharacters.js
+++ b/src/systems/ui/alternatePresentCharacters.js
@@ -1,5 +1,6 @@
 import { extensionSettings } from '../../core/state.js';
 import { i18n } from '../../core/i18n.js';
+import { getSafeImageSrc } from '../../utils/imageUrls.js';
 import { getExpressionPortraitForCharacter } from '../integration/expressionSync.js';
 import {
     getPresentCharactersTrackerData,
@@ -34,15 +35,6 @@ function ensureAlternatePresentCharactersPanel() {
     return $panel;
 }
 
-function escapeHtml(value) {
-    return String(value ?? '')
-        .replace(/&/g, '&')
-        .replace(/</g, '&lt;')
-        .replace(/>/g, '&gt;')
-        .replace(/"/g, '&quot;')
-        .replace(/'/g, '&#39;');
-}
-
 function hexToRgba(hex, opacity = 100) {
     const r = parseInt(hex.slice(1, 3), 16);
     const g = parseInt(hex.slice(3, 5), 16);
@@ -51,6 +43,44 @@ function hexToRgba(hex, opacity = 100) {
     return `rgba(${r}, ${g}, ${b}, ${a})`;
 }
 
+function handlePortraitLoadError() {
+    this.style.opacity = '0.5';
+    $(this).off('error', handlePortraitLoadError);
+}
+
+function createAlternatePresentCharacterCard(character) {
+    const rawPortrait = (extensionSettings.syncExpressionsToPresentCharacters
+        ? getExpressionPortraitForCharacter(character.name)
+        : null) || resolvePresentCharacterPortrait(character.name);
+    const portrait = getSafeImageSrc(rawPortrait);
+    const name = String(character.name || '');
+
+    const $card = $('<div class="rpg-alt-present-character"></div>')
+        .attr('data-character-name', name)
+        .attr('title', name);
+
+    const $portrait = $('<div class="rpg-alt-present-character__portrait"></div>');
+    const $image = $('<img />')
+        .attr({
+            alt: name,
+            loading: 'lazy'
+        })
+        .on('error', handlePortraitLoadError);
+
+    if (portrait) {
+        $image.attr('src', portrait);
+    }
+
+    const $meta = $('<div class="rpg-alt-present-character__meta"></div>');
+    const $name = $('<div class="rpg-alt-present-character__name"></div>').text(name);
+
+    $portrait.append($image);
+    $meta.append($name);
+    $card.append($portrait, $meta);
+
+    return $card;
+}
+
 export function removeAlternatePresentCharactersPanel() {
     $(`#${PANEL_ID}`).remove();
 }
@@ -120,42 +150,28 @@ export function renderAlternatePresentCharacters({ useCommittedFallback = true }
 
     const title = i18n.getTranslation('template.trackerEditorModal.tabs.presentCharacters') || 'Present Characters';
 
-    let html = `
-        <div class="rpg-alt-present-characters__header">
-            <div class="rpg-alt-present-characters__title">
-                <i class="fa-solid fa-users" aria-hidden="true"></i>
-                <span>${escapeHtml(title)}</span>
-            </div>
-            <div class="rpg-alt-present-characters__count">${presentCharacters.length}</div>
-        </div>
-        <div class="rpg-alt-present-characters__scroll">
-            <div class="rpg-alt-present-characters__track">
-    `;
+    const $panel = ensureAlternatePresentCharactersPanel();
+    const $header = $('<div class="rpg-alt-present-characters__header"></div>');
+    const $headerTitle = $('<div class="rpg-alt-present-characters__title"></div>');
+    const $scroll = $('<div class="rpg-alt-present-characters__scroll"></div>');
+    const $track = $('<div class="rpg-alt-present-characters__track"></div>');
+
+    $headerTitle.append(
+        $('<i class="fa-solid fa-users" aria-hidden="true"></i>'),
+        $('<span></span>').text(title)
+    );
+
+    $header.append(
+        $headerTitle,
+        $('<div class="rpg-alt-present-characters__count"></div>').text(String(presentCharacters.length))
+    );
 
     for (const character of presentCharacters) {
-        const portrait = (extensionSettings.syncExpressionsToPresentCharacters
-            ? getExpressionPortraitForCharacter(character.name)
-            : null) || resolvePresentCharacterPortrait(character.name);
-        const name = escapeHtml(character.name || '');
-
-        html += `
-            <div class="rpg-alt-present-character" data-character-name="${name}" title="${name}">
-                <div class="rpg-alt-present-character__portrait">
-                    <img src="${portrait}" alt="${name}" loading="lazy" onerror="this.style.opacity='0.5';this.onerror=null;" />
-                </div>
-                <div class="rpg-alt-present-character__meta">
-                    <div class="rpg-alt-present-character__name">${name}</div>
-                </div>
-            </div>
-        `;
+        $track.append(createAlternatePresentCharacterCard(character));
     }
 
-    html += `
-            </div>
-        </div>
-    `;
+    $scroll.append($track);
 
-    const $panel = ensureAlternatePresentCharactersPanel();
-    $panel.html(html).show();
+    $panel.empty().append($header, $scroll).show();
     syncAlternatePresentCharactersTheme();
 }
diff --git a/src/utils/imageUrls.js b/src/utils/imageUrls.js
new file mode 100644
index 0000000..df0a0aa
--- /dev/null
+++ b/src/utils/imageUrls.js
@@ -0,0 +1,53 @@
+/**
+ * Image URL Utilities Module
+ * Centralizes validation for image sources captured from DOM or settings.
+ */
+
+const DEFAULT_IMAGE_BASE_URL = typeof window !== 'undefined'
+    ? window.location.href
+    : 'http://localhost/';
+
+export function normalizeImageSrc(src) {
+    return String(src ?? '').trim();
+}
+
+export function resolveImageUrl(src, baseUrl = DEFAULT_IMAGE_BASE_URL) {
+    const normalized = normalizeImageSrc(src);
+    if (!normalized) {
+        return null;
+    }
+
+    try {
+        return new URL(normalized, baseUrl);
+    } catch {
+        return null;
+    }
+}
+
+export function isSafeImageSrc(src) {
+    const normalized = normalizeImageSrc(src);
+    if (!normalized) {
+        return false;
+    }
+
+    const candidate = resolveImageUrl(normalized);
+    if (!candidate) {
+        return false;
+    }
+
+    const protocol = candidate.protocol.toLowerCase();
+    if (protocol === 'http:' || protocol === 'https:' || protocol === 'blob:') {
+        return true;
+    }
+
+    if (protocol === 'data:') {
+        return normalized.toLowerCase().startsWith('data:image/');
+    }
+
+    return false;
+}
+
+export function getSafeImageSrc(src) {
+    const normalized = normalizeImageSrc(src);
+    return isSafeImageSrc(normalized) ? normalized : null;
+}