[ImageResizer] Default values for new size (#13285)

* Code changes

* small fix in unittests

* Add new Unit Test

* Fix tests

* fix typo

* remove unused code from unit test

* Update resource string name

* Add name counter

* comment update

* Update tests

src/settings-ui/Microsoft.PowerToys.Settings.UI/Strings/en-us/Resources.resw

@@ -875,7 +875,7 @@
   <data name="ImageResizer_UseOriginalDate.Header" xml:space="preserve">
     <value>Use original date modified</value>
   </data>
-    <data name="ImageResizer_UseOriginalDate.Description" xml:space="preserve">
+  <data name="ImageResizer_UseOriginalDate.Description" xml:space="preserve">
     <value>Keep the original modified date of the file (instead of the resize date)</value>
   </data>
   <data name="Encoding.Header" xml:space="preserve">
@@ -1620,4 +1620,8 @@ From there, simply click on a Markdown file, PDF file or SVG icon in the File Ex
   <data name="FancyZones_SpanZonesAcrossMonitorsPrerequisites.Text" xml:space="preserve">
     <value>All monitors must have the same DPI scaling and will be treated as one large combined rectangle which contains all monitors</value>
   </data>
+  <data name="ImageResizer_DefaultSize_NewSizePrefix" xml:space="preserve">
+    <value>New size</value>
+    <comment>First part of the default name of new sizes that can be added in PT's settings ui.</comment>
+  </data>
 </root>

src/settings-ui/Microsoft.PowerToys.Settings.UI/Views/ImageResizerPage.xaml.cs

@@ -72,7 +72,7 @@ namespace Microsoft.PowerToys.Settings.UI.Views
         {
             try
             {
-                ViewModel.AddRow();
+                ViewModel.AddRow(ResourceLoader.GetForCurrentView().GetString("ImageResizer_DefaultSize_NewSizePrefix"));
             }
             catch (Exception ex)
             {