diff --git a/src/main/java/chzzk/grassdiary/domain/diary/service/DiaryService.java b/src/main/java/chzzk/grassdiary/domain/diary/service/DiaryService.java
index c2572aee..14c41a39 100644
--- a/src/main/java/chzzk/grassdiary/domain/diary/service/DiaryService.java
+++ b/src/main/java/chzzk/grassdiary/domain/diary/service/DiaryService.java
@@ -112,7 +112,7 @@ public DiaryDetailDTO findById(Long diaryId, Long logInMemberId) {
     public List<ImageDTO> getImagesByDiary(Long diaryId) {
         return diaryToImageDAO.findByDiaryId(diaryId)
                 .stream()
-                .map(image -> ImageDTO.from(image, imageService.getImageURLByImage(image.getImage()), image.getImage().getImageName()))
+                .map(image -> ImageDTO.from(image, imageService.getImageURLByImage(image.getImage()), image.getImage().getImageName(), image.getImage().getSize()))
                 .toList();
     }
 
diff --git a/src/main/java/chzzk/grassdiary/domain/image/controller/ImageController.java b/src/main/java/chzzk/grassdiary/domain/image/controller/ImageController.java
index c2f625bc..bd82c7d6 100644
--- a/src/main/java/chzzk/grassdiary/domain/image/controller/ImageController.java
+++ b/src/main/java/chzzk/grassdiary/domain/image/controller/ImageController.java
@@ -31,6 +31,9 @@ public class ImageController {
     String THEME_SHOP_URL = "static/images/theme_shop.jpg";
 
     @PostMapping("/diary")
+    @Operation(
+            summary = "일기 이미지 저장",
+            description = "이미지 저장시 사이즈는 KB(킬로바이트) 단위")
     public ResponseEntity<?> uploadDiaryImage(
             @RequestPart MultipartFile image
     ) {
diff --git a/src/main/java/chzzk/grassdiary/domain/image/dto/ImageDTO.java b/src/main/java/chzzk/grassdiary/domain/image/dto/ImageDTO.java
index a5d53d28..320f5cfe 100644
--- a/src/main/java/chzzk/grassdiary/domain/image/dto/ImageDTO.java
+++ b/src/main/java/chzzk/grassdiary/domain/image/dto/ImageDTO.java
@@ -7,9 +7,10 @@
 public record ImageDTO (
         Long imageId,
         String imageURL,
-        String imageName
+        String imageName,
+        Long imageSize
 ) {
-    public static ImageDTO from(DiaryToImage diaryToImage, String imageURL, String imageName) {
-        return new ImageDTO(diaryToImage.getImage().getId(), imageURL, imageName);
+    public static ImageDTO from(DiaryToImage diaryToImage, String imageURL, String imageName, Long imageSize) {
+        return new ImageDTO(diaryToImage.getImage().getId(), imageURL, imageName, imageSize);
     }
 }
diff --git a/src/main/java/chzzk/grassdiary/domain/image/entity/Image.java b/src/main/java/chzzk/grassdiary/domain/image/entity/Image.java
index 83ab074d..e2b15eee 100644
--- a/src/main/java/chzzk/grassdiary/domain/image/entity/Image.java
+++ b/src/main/java/chzzk/grassdiary/domain/image/entity/Image.java
@@ -24,8 +24,11 @@ public class Image extends BaseCreatedTimeEntity {
 
     private String imageName;
 
-    public Image(String imagePath, String imageName) {
+    private Long size;
+
+    public Image(String imagePath, String imageName, Long size) {
         this.imagePath = imagePath;
         this.imageName = imageName;
+        this.size = size;
     }
 }
diff --git a/src/main/java/chzzk/grassdiary/domain/image/service/ImageService.java b/src/main/java/chzzk/grassdiary/domain/image/service/ImageService.java
index 4fd284e0..8220300f 100644
--- a/src/main/java/chzzk/grassdiary/domain/image/service/ImageService.java
+++ b/src/main/java/chzzk/grassdiary/domain/image/service/ImageService.java
@@ -31,9 +31,10 @@ public ImageDTO uploadImage(MultipartFile image, FileFolder category) {
             throw new SystemException(ClientErrorCode.IMAGE_FILE_EMPTY);
         }
         String imagePath = awsS3Service.uploadBucket(image, category);
-        Image uploadedImage = imageDAO.save(new Image(imagePath, image.getOriginalFilename()));
+        long sizeInKB = image.getSize() / 1024; 
+        Image uploadedImage = imageDAO.save(new Image(imagePath, image.getOriginalFilename(), sizeInKB));
 
-        return new ImageDTO(uploadedImage.getId(), baseURL + imagePath, image.getOriginalFilename());
+        return new ImageDTO(uploadedImage.getId(), baseURL + imagePath, image.getOriginalFilename(), sizeInKB);
     }
 
     /**