修复预交付界面，图片损坏bug

src/main/java/com/mooctest/service/FinalReportService.java

@@ -68,7 +68,9 @@ public class FinalReportService {
         return frs.stream().map(finalReport -> {
             FinalReportDTO dto = new FinalReportDTO();
             BeanUtils.copyProperties(finalReport, dto);
-            dto.setImgUrls(finalReport.getImgUrls().split(","));
+            if(finalReport.getImgUrls()!=null&&!finalReport.getImgUrls().equals("")){
+                dto.setImgUrls(finalReport.getImgUrls().split(","));
+            }
             return dto;
         }).collect(Collectors.toList());
     }

src/main/resources/templates/final_report_list.html

@@ -141,18 +141,23 @@
 </th:block>
 </body>
 </html>
+
 <div class="modal fade bs-example-modal-lg text-center" id="imgModal" tabindex="-1" role="dialog"
      aria-labelledby="myLargeModalLabel">
 
-    <div class="modal-dialog modal-lg" style="display: inline-block; width: 300px;">
-        <div class="modal-content">
-            <img id="imgInModalID"
-                 class="carousel-inner img-responsive img-rounded"
-                 onclick="closeImageViewer()"
-                 onmouseover="this.style.cursor='pointer';this.style.cursor='hand'"
-                 onmouseout="this.style.cursor='default'"
-
-            />
+    <div class="modal-dialog modal-lg" style="display: inline-block; max-width: 900px; max-height: 600px">
+        <div class="modal-content" style="background:  transparent">
+            <center>
+                <img id="imgInModalID"
+                     class="carousel-inner img-responsive "
+                     onclick="closeImageViewer()"
+                     onmouseover="this.style.cursor='pointer';this.style.cursor='hand'"
+                     onmouseout="this.style.cursor='default'"
+                     style="max-height: 90vh;
+                     max-width: 90vw;
+                     object-fit: contain;"
+                />
+            </center>
         </div>
     </div>