diff --git a/Riot/Modules/MatrixKit/Controllers/MXKAttachmentsViewController.h b/Riot/Modules/Room/Attachements/MXKAttachmentsViewController.h
similarity index 100%
rename from Riot/Modules/MatrixKit/Controllers/MXKAttachmentsViewController.h
rename to Riot/Modules/Room/Attachements/MXKAttachmentsViewController.h
diff --git a/Riot/Modules/MatrixKit/Controllers/MXKAttachmentsViewController.m b/Riot/Modules/Room/Attachements/MXKAttachmentsViewController.m
similarity index 98%
rename from Riot/Modules/MatrixKit/Controllers/MXKAttachmentsViewController.m
rename to Riot/Modules/Room/Attachements/MXKAttachmentsViewController.m
index 721b9e08bc..6633ce7b37 100644
--- a/Riot/Modules/MatrixKit/Controllers/MXKAttachmentsViewController.m
+++ b/Riot/Modules/Room/Attachements/MXKAttachmentsViewController.m
@@ -38,6 +38,8 @@
 
 #import "MXKSwiftHeader.h"
 
+#import "LegacyAppDelegate.h"
+
 @interface MXKAttachmentsViewController () <UINavigationControllerDelegate, UIViewControllerTransitioningDelegate>
 {
     /**
@@ -472,7 +474,9 @@ - (void)refreshCurrentVisibleItemIndex
     // Check whether the collection is actually rendered
     if (_attachmentsCollection.contentSize.width)
     {
-        currentVisibleItemIndex = _attachmentsCollection.contentOffset.x / [[UIScreen mainScreen] bounds].size.width;
+        // Get the window from the app delegate as this can be called before the view is presented.
+        UIWindow *window = LegacyAppDelegate.theDelegate.window;
+        currentVisibleItemIndex = _attachmentsCollection.contentOffset.x / window.bounds.size.width;
     }
     else
     {
@@ -484,9 +488,12 @@ - (void)refreshAttachmentCollectionContentOffset
 {
     if (currentVisibleItemIndex != NSNotFound && _attachmentsCollection)
     {
+        // Get the window from the app delegate as this can be called before the view is presented.
+        UIWindow *window = LegacyAppDelegate.theDelegate.window;
+        
         // Set the content offset to display the current attachment
         CGPoint contentOffset = _attachmentsCollection.contentOffset;
-        contentOffset.x = currentVisibleItemIndex * [[UIScreen mainScreen] bounds].size.width;
+        contentOffset.x = currentVisibleItemIndex * window.bounds.size.width;
         _attachmentsCollection.contentOffset = contentOffset;
     }
 }
@@ -1118,7 +1125,8 @@ - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
 
 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
 {
-    return [[UIScreen mainScreen] bounds].size;
+    // Use the window from the app delegate as this can be called before the view is presented.
+    return LegacyAppDelegate.theDelegate.window.bounds.size;
 }
 
 #pragma mark - Movie Player
diff --git a/Riot/Modules/MatrixKit/Controllers/MXKAttachmentsViewController.xib b/Riot/Modules/Room/Attachements/MXKAttachmentsViewController.xib
similarity index 100%
rename from Riot/Modules/MatrixKit/Controllers/MXKAttachmentsViewController.xib
rename to Riot/Modules/Room/Attachements/MXKAttachmentsViewController.xib
diff --git a/changelog.d/pr-6339.bugfix b/changelog.d/pr-6339.bugfix
new file mode 100644
index 0000000000..9a79090dfa
--- /dev/null
+++ b/changelog.d/pr-6339.bugfix
@@ -0,0 +1 @@
+Media: Fix size issues when opening media on an iPad whilst multi-tasking.
\ No newline at end of file