diff --git a/back/main.py b/back/main.py
index 5d81a00..a3d9f2e 100644
--- a/back/main.py
+++ b/back/main.py
@@ -7,6 +7,7 @@ from sqlalchemy.orm import foreign
 import os
 import uuid
 import json
+import filetype
 from datetime import datetime
 
 app = Flask(__name__)
@@ -24,7 +25,7 @@ db = SQLAlchemy(app)
 # 全局配置变量
 NEED_AUDIT = True
 FILE_SIZE_LIMIT_MB = 10.0
-FILE_FORMATS = ["png", "jpg", "jpeg", "gif", "webp"]
+FILE_FORMATS = ["image/png", "image/jpeg", "image/gif", "image/webp"]
 
 def now_time():
     return datetime.now()
@@ -165,7 +166,7 @@ def load_config():
                         else:
                             parsed = raw
                         if isinstance(parsed, list):
-                            FILE_FORMATS = [str(x).strip().lstrip('.').lower() for x in parsed if str(x).strip()]
+                            FILE_FORMATS = [str(x).strip().lower() for x in parsed if str(x).strip()]
                     except Exception:
                         pass
         except Exception as e:
@@ -211,17 +212,6 @@ def save_hashtags(tag_type, target_id, hashtopic):
         )
         db.session.add(new_tag)
 
-def detect_image_type(header: bytes):
-    if header.startswith(b"\xFF\xD8\xFF"):
-        return "jpeg"
-    if header.startswith(b"\x89PNG\r\n\x1a\n"):
-        return "png"
-    if header.startswith(b"GIF87a") or header.startswith(b"GIF89a"):
-        return "gif"
-    if header.startswith(b"RIFF") and len(header) >= 12 and header[8:12] == b"WEBP":
-        return "webp"
-    return None
-    
 # --- 用户普通api端点 ---
 @app.route('/api/settings', methods=['GET'])
 def get_settings():
@@ -512,24 +502,15 @@ def upload_pic():
                 return jsonify({"code": 2006, "data": "上传的图片超出限制大小"})
 
         ext = os.path.splitext(file.filename)[1].lstrip('.').lower()
-        if not ext or (FILE_FORMATS and ext not in FILE_FORMATS):
-            return jsonify({"code": 2007, "data": "上传的文件类型不支持"})
-
-        header = file.read(512)
+        kind = filetype.guess(file.read(5120))
         file.seek(0)
-        detected = detect_image_type(header)
-        ext_map = {
-            'jpg': 'jpeg',
-            'jpeg': 'jpeg',
-            'png': 'png',
-            'gif': 'gif',
-            'webp': 'webp',
-        }
-        expected = ext_map.get(ext)
-        if not expected or detected != expected:
+        detected_mime = kind.mime if kind else None
+        if not detected_mime or (FILE_FORMATS and detected_mime.lower() not in FILE_FORMATS):
             return jsonify({"code": 2007, "data": "上传的文件类型不支持"})
 
-        filename = f"{uuid.uuid4().hex}.{ext}"
+        if not ext and kind:
+            ext = kind.extension
+        filename = f"{uuid.uuid4().hex}.{ext}" if ext else uuid.uuid4().hex
         filepath = os.path.join(IMG_DIR, filename)
         file.save(filepath)
 
diff --git a/back/requirements.txt b/back/requirements.txt
index 21ff148..37d95ad 100644
--- a/back/requirements.txt
+++ b/back/requirements.txt
@@ -1,3 +1,4 @@
 Flask>=3.0.3
 Flask-CORS>=4.0.1
-Flask-SQLAlchemy>=3.1.1
\ No newline at end of file
+Flask-SQLAlchemy>=3.1.1
+filetype>=1.2.0
diff --git a/front/src/api.ts b/front/src/api.ts
index 3fd9097..d3c7bdc 100644
--- a/front/src/api.ts
+++ b/front/src/api.ts
@@ -21,12 +21,12 @@ export const getSettings = async (): Promise<SiteSettings> => {
       let fileFormats: string[] | undefined;
       if (data.file_formats) {
         if (Array.isArray(data.file_formats)) {
-          fileFormats = data.file_formats.map((x: any) => String(x).trim().replace(/^\./, '').toLowerCase()).filter((x: string) => x);
+          fileFormats = data.file_formats.map((x: any) => String(x).trim().toLowerCase()).filter((x: string) => x);
         } else if (typeof data.file_formats === 'string') {
           try {
             const parsed = JSON.parse(data.file_formats);
             if (Array.isArray(parsed)) {
-              fileFormats = parsed.map((x: any) => String(x).trim().replace(/^\./, '').toLowerCase()).filter((x: string) => x);
+              fileFormats = parsed.map((x: any) => String(x).trim().toLowerCase()).filter((x: string) => x);
             }
           } catch {
             // ignore parse error
diff --git a/front/src/components/CreatePost.tsx b/front/src/components/CreatePost.tsx
index a11dcd3..976be93 100644
--- a/front/src/components/CreatePost.tsx
+++ b/front/src/components/CreatePost.tsx
@@ -292,8 +292,8 @@ const CreatePost: React.FC = () => {
     }
     const formats = settings?.fileFormats;
     if (formats && formats.length > 0) {
-      const ext = file.name.split('.').pop()?.toLowerCase() || '';
-      if (!ext || !formats.includes(ext)) {
+      const mime = (file.type || '').toLowerCase();
+      if (!mime || !formats.includes(mime)) {
         dispatchToast(
           <Toast>
             <ToastTitle>上传的文件类型不支持</ToastTitle>