feat: add Image.resolveAssetSource api

packages/react-native-web-docs/src/pages/docs/components/image.md

@@ -97,6 +97,10 @@ Prefetches a remote image for later use by downloading it. Once an image has bee
 Performs cache interrogation. Returns a mapping from URL to cache status: "disk", "memory", "disk/memory". If a requested URL is not in the mapping, it means it's not in the cache.
 {% endcall %}
 
+{% call macro.prop('resolveAssetSource', '?(source: Source) => { uri: string, width?: number, height?: number }') %}
+Resolves an asset reference into an object which has the properties uri, width, and height.
+{% endcall %}
+
 ---
 
 ## Examples

packages/react-native-web/src/exports/Image/index.js

@@ -8,7 +8,7 @@
  * @flow
  */
 
-import type { ImageProps } from './types';
+import type { ImageProps, Source } from './types';
 
 import * as React from 'react';
 import createElement from '../createElement';
@@ -164,6 +164,7 @@ interface ImageStatics {
     success: (width: number, height: number) => void,
     failure: () => void
   ) => void;
+  resolveAssetSource: (source: Source) => { uri: string, width?: number, height?: number };
   prefetch: (uri: string) => Promise<void>;
   queryCache: (
     uris: Array<string>
@@ -359,6 +360,21 @@ const ImageWithStatics = (Image: React.AbstractComponent<
 > &
   ImageStatics);
 
+ImageWithStatics.resolveAssetSource = function resolveAssetSource(
+  source
+): { uri: string, width?: number, height?: number } {
+  const uri = resolveAssetUri(source) || '';
+  const dimensions = resolveAssetDimensions(source) || {};
+  let width, height;
+  if (typeof dimensions.width === 'number') {
+    width = dimensions.width;
+  }
+  if (typeof dimensions.height === 'number') {
+    height = dimensions.height;
+  }
+  return { uri, width, height };
+};
+
 ImageWithStatics.getSize = function (uri, success, failure) {
   ImageLoader.getSize(uri, success, failure);
 };