Is it possible to fetch image Urls array for every post in latest.json?
I also care https://meta.discourse.org/latest.json
The answer is no currently.
Discourse team are doing work on image exposure in the Topic List but this will just serve a single representative thumbnail from the first Post I believe. (Ignoring any additional thumbnails of different dimensions)
This new, additional feature of the API is very welcome however.
You could change the API with your own plugin but that’s unlikely to perform well unless you set up some kind of batch process to pre calculate the values.