Allow use of AI-generated imagery for blog post content

The following discussion from !116897 (merged) should be addressed:

@Sgittlen started a discussion: (+4 comments). In it it was decided to stick to an unsplash-like image.

I think we should be able to use more novel or custom images, as long as we have the rights to do so.

Example

I made an alternative banner image using an AI tool called Dall-e, which are free to use. I modified the image so the screen read "$1,000,000" but other than that it was pretty neat! Better than the standard gloomy hacker stock imagery, or a padlock.

...users get full usage rights to commercialize the images they create with DALL·E, including the right to reprint, sell, and merchandise. This includes images they generated during the research preview.

https://openai.com/blog/dall-e-now-available-in-beta

Try it out

There's a super accessible, but lower-powered, version of DALL-E here: https://www.craiyon.com/

Or sign up for this which has some free credits to get started: https://openai.com/dall-e-2/

Proposal

Allow AI-generated images, e.g. from DALL-E, as a permitted source of images.