diff --git a/schema/article.schema.json b/schema/article.schema.json
index 42fe8bfe..9dd17e29 100644
--- a/schema/article.schema.json
+++ b/schema/article.schema.json
@@ -66,7 +66,6 @@
               "properties": {
                 "_xlarge": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Extra Large",
                   "description": "Extra large background image, e.g. hd laptop/desktop computers",
                   "_backboneForms": {
@@ -76,7 +75,6 @@
                 },
                 "_large": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Large",
                   "description": "Large background image, e.g. laptop/desktop computers",
                   "_backboneForms": {
@@ -86,7 +84,6 @@
                 },
                 "_medium": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Medium",
                   "description": "Medium background image, e.g. tablet devices",
                   "_backboneForms": {
@@ -96,7 +93,6 @@
                 },
                 "_small": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Small",
                   "description": "Small background image, e.g. mobile / cellphones",
                   "_backboneForms": {
diff --git a/schema/block.schema.json b/schema/block.schema.json
index c2b4fa36..0557663a 100644
--- a/schema/block.schema.json
+++ b/schema/block.schema.json
@@ -66,7 +66,6 @@
               "properties": {
                 "_xlarge": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Extra large",
                   "description": "Extra large background image, e.g. hd laptop/desktop computers",
                   "_backboneForms": {
@@ -76,7 +75,6 @@
                 },
                 "_large": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Large",
                   "description": "Large background image, e.g. laptop/desktop computers",
                   "_backboneForms": {
@@ -86,7 +84,6 @@
                 },
                 "_medium": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Medium",
                   "description": "Medium background image, e.g. tablet devices",
                   "_backboneForms": {
@@ -96,7 +93,6 @@
                 },
                 "_small": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Small",
                   "description": "Small background image, e.g. mobile / cellphones",
                   "_backboneForms": {
diff --git a/schema/contentobject.schema.json b/schema/contentobject.schema.json
index 6606b48d..cd2c3d44 100644
--- a/schema/contentobject.schema.json
+++ b/schema/contentobject.schema.json
@@ -20,7 +20,6 @@
               "properties": {
                 "_xlarge": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Extra large",
                   "description": "Extra large background image, e.g. hd laptop/desktop computers",
                   "_backboneForms": {
@@ -30,7 +29,6 @@
                 },
                 "_large": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Large",
                   "description": "Large background image, e.g. laptop/desktop computers",
                   "_backboneForms": {
@@ -40,7 +38,6 @@
                 },
                 "_medium": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Medium",
                   "description": "Medium background image, e.g. tablet devices",
                   "_backboneForms": {
@@ -50,7 +47,6 @@
                 },
                 "_small": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Small",
                   "description": "Small background image, e.g. mobile / cellphones",
                   "_backboneForms": {
@@ -200,7 +196,6 @@
                   "properties": {
                     "_xlarge": {
                       "type": "string",
-                      "isObjectId": true,
                       "title": "Extra large",
                       "description": "Extra large background image, e.g. hd laptop/desktop computers",
                       "_backboneForms": {
@@ -210,7 +205,6 @@
                     },
                     "_large": {
                       "type": "string",
-                      "isObjectId": true,
                       "title": "Large",
                       "description": "Large background image, e.g. laptop/desktop computers",
                       "_backboneForms": {
@@ -220,7 +214,6 @@
                     },
                     "_medium": {
                       "type": "string",
-                      "isObjectId": true,
                       "title": "Medium",
                       "description": "Medium background image, e.g. tablet devices",
                       "_backboneForms": {
@@ -230,7 +223,6 @@
                     },
                     "_small": {
                       "type": "string",
-                      "isObjectId": true,
                       "title": "Small",
                       "description": "Small background image, e.g. mobile / cellphones",
                       "_backboneForms": {
diff --git a/schema/course.schema.json b/schema/course.schema.json
index f192d4f7..24333098 100644
--- a/schema/course.schema.json
+++ b/schema/course.schema.json
@@ -20,7 +20,6 @@
               "properties": {
                 "_src": {
                   "type": "string",
-                  "isObjectId": true,
                   "title": "Image",
                   "description": "Select a favicon to improve user experience and enforce brand consistency. This will be displayed in places like your browser's address bar, page tabs and bookmarks menu. Usually, a favicon is 16 x 16 pixels in size and stored in the GIF, PNG, or ICO file format.",
                   "_backboneForms": {