elf-pavlikaaronpk, what do you think about uploading image with seperate request and then uploading JSON object which has links to them? it looks bit similar and creating other resources which have their own URL but which you may not want to 'nest' http://indiewebcamp.com/micropub#Nested_Microformat_Objects
elf-pavlikaaronpk, when i played with prototypoing https://github.com/dspace-ng each account could set dedicated server for binary uploads and use different one for profile and all the JSON of activities... sometimes image/png can go to one domain and 'social artifact' application/ld+json to another one
elf-pavliki will just give it a try again and implement uploading PNG and JSON-LD in two requests to two different domains for LDP + Hydra demos I prepare for our F2F3 in Paris!