Google's John Mueller said this morning on Twitter that the Fetch and Render tool within the Google Search Console is the closest representation of what Google sees when they crawl your site. It is better for that purpose than the Google cache. John added that "if it works there [fetch and render], it'll work for search."
While he added that the cache itself is "just raw HTML." So looking at the cache was the old fetch and render, you can now really see what Google can see by going into Google Search Console and using the Fetch & Render tool.
John later added that "the cache is the raw HTML. Without the raw HTML, the image won't be loaded. If the layout doesn't look perfect, that's usually OK."
Here are his tweets:
@TraianNeacsu @methode Fetch & render is closest - if it works there, it'll work for search. Cache = just raw HTML.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) May 29, 2017
@micahfk @TraianNeacsu @methode The cache is the raw HTML. Without the raw HTML, the image won't be loaded. If the layout doesn't look perfect, that's usually OK.
— John ☆.o(≧▽≦)o.☆ (@JohnMu) May 30, 2017
Forum discussion at Twitter.