prevent undefined error & remove unexistent function

src/views/project/Project_edit.vue

 <template>
   <div class="fourteen wide column">
-    <div
-      :class="{active: loading}"
-      class="ui inverted dimmer"
-    >
+    <div :class="{ active: loading }" class="ui inverted dimmer">
       <div class="ui text loader">
         Projet en cours de création. Vous allez être redirigé.
       </div>
@@ -346,7 +343,7 @@ export default {
 
     postProjectThumbnail(projectSlug) {
       //* send img to the backend when feature_type is created
-      if (this.isValidImage(this.fileToImport)) {
+      if (this.fileToImport) {
         let formData = new FormData();
         formData.append("file", this.fileToImport);
         const url =
@@ -432,7 +429,7 @@ export default {
             this.loading = false;
           })
           .catch((error) => {
-            if (error.response.data.title[0]) {
+            if (error.response && error.response.data.title[0]) {
               this.errors.title.push(error.response.data.title[0]);
             }
             this.loading = false;
@@ -455,7 +452,7 @@ export default {
             }
           })
           .catch((error) => {
-            if (error.response.data.title[0]) {
+            if (error.response && error.response.data.title[0]) {
               this.errors.title.push(error.response.data.title[0]);
             }
             throw error;