[refactor] 활동사진 지연로딩 제거

frontend/src/components/common/LazyImage/LazyImage.test.tsx

@@ -85,24 +85,6 @@ describe('LazyImage 컴포넌트', () => {
     expect(mockDisconnect).toHaveBeenCalled();
   });
 
-  it('index prop에 따라 지연 시간이 적용되어야 함', () => {
-    render(<LazyImage {...defaultProps} index={2} delayMs={100} />);
-
-    const [[callback]] = mockIntersectionObserver.mock.calls;
-    const entry = { isIntersecting: true };
-    act(() => {
-      callback([entry], {} as IntersectionObserver);
-    });
-
-    expect(screen.queryByRole('img')).not.toBeInTheDocument();
-
-    act(() => {
-      jest.advanceTimersByTime(200);
-    });
-
-    expect(screen.getByRole('img')).toBeInTheDocument();
-  });
-
   it('onError prop이 호출되어야 함', async () => {
     const onError = jest.fn();
     render(<LazyImage {...defaultProps} onError={onError} />);

frontend/src/components/common/LazyImage/LazyImage.tsx

@@ -4,49 +4,34 @@ interface LazyImageProps {
   src: string;
   alt: string;
   onError?: () => void;
-  index?: number;
-  delayMs?: number;
 }
 
-const LazyImage = ({
-  src,
-  alt,
-  onError,
-  index = 0,
-  delayMs = 200,
-}: LazyImageProps) => {
-  const [shouldLoad, setShouldLoad] = useState(false);
+const LazyImage = ({ src, alt, onError }: LazyImageProps) => {
   const [isVisible, setIsVisible] = useState(false);
   const imgRef = useRef<HTMLImageElement | null>(null);
 
   useEffect(() => {
-    const observer = new IntersectionObserver(
-      ([entry]) => {
-        if (entry.isIntersecting) {
-          const delay = index * delayMs;
-          const timeout = setTimeout(() => {
-            setShouldLoad(true);
-          }, delay);
-          observer.disconnect();
-
-          return () => clearTimeout(timeout);
-        }
-      },
-      { threshold: 0.1 },
-    );
+    let timeout: ReturnType<typeof setTimeout>;
+
+    const observer = new IntersectionObserver(([entry]) => {
+      if (entry.isIntersecting) {
+        const delay = 100;
+        timeout = setTimeout(() => {
+          setIsVisible(true);
+        }, delay);
+        observer.disconnect();
+      }
+    });
 
     if (imgRef.current) {
       observer.observe(imgRef.current);
     }
 
-    return () => observer.disconnect();
-  }, [index, delayMs]);
-
-  useEffect(() => {
-    if (shouldLoad) {
-      setIsVisible(true);
-    }
-  }, [shouldLoad]);
+    return () => {
+      observer.disconnect();
+      clearTimeout(timeout);
+    };
+  }, []);
 
   return isVisible ? (
     <img ref={imgRef} src={src} alt={alt} onError={onError} />

frontend/src/pages/ClubDetailPage/components/PhotoList/PhotoList.tsx

@@ -104,8 +104,6 @@ const PhotoList = ({ feeds: photos, sectionRefs }: PhotoListProps) => {
                   <LazyImage
                     src={url}
                     alt={`활동 사진 ${index + 1}`}
-                    index={index}
-                    delayMs={200}
                     onError={() => handleImageError(index)}
                   />
                 ) : (