change(item): image size to reference big instead of large

- added preview as size for image item in case we have items that
  need to have the card 400px width
- set the big value as default as a safer default

src/blocks/Item/Item.jsx

@@ -8,10 +8,10 @@ function Item({
   extra,
   header,
   icon,
-  iconSize = 'huge',
+  iconSize = 'big',
   iconTheme,
   image,
-  imageSize = 'tile',
+  imageSize = 'big',
   meta,
   mode = 'view',
   styles = {},
@@ -22,7 +22,7 @@ function Item({
       <UiItem className={cx(styles?.theme)}>
         {assetType === 'image' && image && (
           <UiItem.Image
-            src={`${image}/@@images/image/preview`}
+            src={`${image}/@@images/image/${imageSize}`}
             className={cx('ui', imageSize)}
             alt={header || 'Item image'}
           />

src/blocks/Item/schema.js

@@ -39,9 +39,10 @@ export default ({ data }) => {
         choices: [
           ['small', 'Small'],
           ['medium', 'Medium'],
-          ['large', 'Large'],
+          ['big', 'Large'],
+          ['preview', 'Preview'],
         ],
-        default: 'small',
+        default: 'big',
       },
       icon: {
         title: 'Icon name',
@@ -51,9 +52,9 @@ export default ({ data }) => {
         choices: [
           ['small', 'Small'],
           ['medium', 'Medium'],
-          ['large', 'Large'],
+          ['big', 'Large'],
         ],
-        default: 'small',
+        default: 'big',
       },
       iconTheme: {
         title: 'Icon theme',