So I know that the correct way of identifying pages in a sitemap is like this:
<url> <loc>http://www.example.com/</loc> </url>
If I want to include images in the sitemap, I know that I need to include the image extension and I could then include images like this:
<url> <loc>http://www.example.com/</loc> <image:image> <image:loc>http://example.com/image.jpg</image:loc> </image:image> </url>
My question is, what if I'm using a software that generates the sitemap without an image extension and instead adds images like this:
<url> <loc>http://www.example.com/image.jpg</loc> </url>
I know that Google is ignoring those images (at least it is ignoring them in webmaster) but could this have any negative affect on the functionality of the sitemap.xml file? I know that Google will ignore all canonical tags of a website if there are too many that point to deceptive or error pages — does this same concept apply to sitemaps that have URLs that are not pointing to indexable webpages? Is any documentation on something like this?