diff --git a/pixivclient.cpp b/pixivclient.cpp
index 33b4c4b..07fd8eb 100644
--- a/pixivclient.cpp
+++ b/pixivclient.cpp
@@ -8,6 +8,26 @@ static inline std::optional<std::string> get_1920x960_cover_image(blankie::murl:
 static inline std::optional<std::string> get_original_cover_image(blankie::murl::Url url);
 static inline std::optional<std::string> get_original_profile_picture(blankie::murl::Url url);
 
+const std::string& Images::original_or_thumbnail() const {
+    if (this->original) {
+        return *this->original;
+    }
+    if (!this->thumbnails.empty()) {
+        return this->thumbnails.back();
+    }
+    throw std::runtime_error("Images does not contain any images");
+}
+
+const std::string& Images::thumbnail_or_original() const {
+    if (!this->thumbnails.empty()) {
+        return this->thumbnails.back();
+    }
+    if (this->original) {
+        return *this->original;
+    }
+    throw std::runtime_error("Images does not contain any images");
+}
+
 PixivClient::PixivClient() {
     this->_www_pixiv_net_client.set_keep_alive(true);
     this->_www_pixiv_net_client.set_default_headers({
diff --git a/pixivclient.h b/pixivclient.h
index 76eabb3..c0364c5 100644
--- a/pixivclient.h
+++ b/pixivclient.h
@@ -10,6 +10,9 @@
 struct Images {
     std::optional<std::string> original;
     std::vector<std::string> thumbnails;
+
+    const std::string& original_or_thumbnail() const;
+    const std::string& thumbnail_or_original() const;
 };
 
 struct User {
diff --git a/routes/users/common.cpp b/routes/users/common.cpp
index 450c317..ed069f5 100644
--- a/routes/users/common.cpp
+++ b/routes/users/common.cpp
@@ -4,21 +4,19 @@
 #include "../../pixivclient.h"
 
 static inline Element generate_user_links(const User& user);
-static std::string thumbnail_or_original(const Images& images);
-static std::string original_or_thumbnail(const Images& images);
 
 Element generate_user_header(const User& user, const Config& config) {
     Element header("header");
     if (user.cover_images) {
-        std::string cover_original = proxy_image_url(config, original_or_thumbnail(*user.cover_images));
-        std::string cover_thumbnail = proxy_image_url(config, thumbnail_or_original(*user.cover_images));
+        std::string cover_original = proxy_image_url(config, user.cover_images->original_or_thumbnail());
+        std::string cover_thumbnail = proxy_image_url(config, user.cover_images->thumbnail_or_original());
         header.nodes.push_back(Element("a", {{"href", std::move(cover_original)}}, {
             Element("img", {{"class", "cover"}, {"src", std::move(cover_thumbnail)}}, {})
         }));
     }
 
-    std::string profile_picture_original = proxy_image_url(config, original_or_thumbnail(user.profile_pictures));
-    std::string profile_picture_thumbnail = proxy_image_url(config, thumbnail_or_original(user.profile_pictures));
+    std::string profile_picture_original = proxy_image_url(config, user.profile_pictures.original_or_thumbnail());
+    std::string profile_picture_thumbnail = proxy_image_url(config, user.profile_pictures.thumbnail_or_original());
     header.nodes.push_back(Element("div", {{"class", "usermetadata"}}, {
         Element("a", {{"href", std::move(profile_picture_original)}}, {
             Element("img", {{"class", "profilepicture"}, {"src", std::move(profile_picture_thumbnail)}}, {})
@@ -41,20 +39,3 @@ static inline Element generate_user_links(const User& user) {
     }
     return p;
 }
-
-static std::string thumbnail_or_original(const Images& images) {
-    if (!images.thumbnails.empty()) {
-        return images.thumbnails.back();
-    }
-    return images.original.value_or("");
-}
-
-static std::string original_or_thumbnail(const Images& images) {
-    if (images.original) {
-        return *images.original;
-    }
-    if (!images.thumbnails.empty()) {
-        return images.thumbnails.back();
-    }
-    return "";
-}