Upstream fix

[tennox]

I'm keen to get an upstream fix of some sort, so I created these issues:

• in gridsome plugin: Fix progressive image loading or reference fix in readme gethypervisual/gridsome-plugin-netlify-cms#23
• in netlify docs: docs: add instructions for workaround to enable progressive image loading with gridsome decaporg/decap-cms#5877

[tennox]

One of Netlify's devs pointed out that there's now an option in Netlify CMS to use relative paths:

Some static site generators (e.g. Gatsby) work best when using relative image paths.

This can now be achieved using a per collection media_folder configuration which specifies a relative media folder for the collection.

See here: https://www.netlifycms.org/docs/beta-features/#folder-collections-media-and-public-folder

@tyrion Does this fix the issue? I'm not aware of all the technicalities and edge cases so I can't say for sure.