缩略图contain展示

src/views/chartFrame_manage/css/basePage.scss

@@ -105,7 +105,7 @@
                     height: 0;
                     padding-bottom: 70%;
                     background-color: pink;
-                    background: no-repeat center/cover url('~@/assets/img/document_m/default-img.png');
+                    background: no-repeat center/contain url('~@/assets/img/document_m/default-img.png');
                 }
             }
         }