Questions about gsitemap module

[seowebmaster]

Hello, 

I have some questions about gsitemap module:

1. What does this checkbox label exactly mean: "Check this box if you wish to check the presence of the image files on the server"? Is it related to image indexing?
2. In the generated sitemap, I see that only the large_default image is sent to google. How does it work? Is it possible to send larger images, instead?

3. <url>
   	<loc>
   		<![CDATA[
   			https://example.com/category/1-product_name.html
   		]]>
   	</loc>
   	<priority>0.9</priority>
   	<lastmod>2019-03-28T10:36:01+01:00</lastmod>
   	<changefreq>weekly</changefreq>
   	<image:image>
   		<image:loc>
   			<![CDATA[
   				https://example.com/2-large_default/product_namejpg
   			]]>
   		</image:loc>
   		<image:caption>
   			<![CDATA[
   				Description..
   			]]>
   		</image:caption>
   		<image:title>
   			<![CDATA[ Productname ]]>
   		</image:title>
   	</image:image>
   </url>

    

Thank you

Edited April 4, 2019 by seowebmaster
Edited the title, it was to generic. (see edit history)

[seowebmaster]

Anybody?