Move iMovie Movies to iCloud, Photos, or iCloud Photo Library

Hi All,

I have two macs, one macbook and one imac. I would like to sell my imac because I no longer have room for it. Right now my imac is mostly being used as a media server, so I am looking at cloud or network storage solutions for that. One thing I can't figure out how to replace is iMovie. I have a number of older videos that were imported using a video camera (pre iphone days). I'd like to move these to icloud. I also currently back up my icloud Photo library onto my imac and an external drive via Time Machine. I would like to retain at least one physical backup of this. Trouble is, my macbook doesn't have that kind of space (my iMac as a 3TB HDD). So basically what i need is a local backup, and I need to move my movies to a format that doesn't require an imac to view them (I plan to keep the macbook so a network solution could work). I would love to hear any ideas or suggestions.

The only thing I've come up with is to buy a mac mini, put a big hdd in it, and remote desktop into it from the macbook when I want to work on videos. But I really don't want to do that.

Thanks!