Late to the party here but Google Backup and Sync is great, backs up the entire PC or Mac and your external hard drives, or you can specify exactly which folders you want backed up, it backs up virtually all image file types, raws and all. I've used it for over a year now. Loads of storage for cheap.
On the other hand, if you have Lightroom CC (not Classic), you can have your entire catalogue and originals reside in the "cloud" and have them accessible everywhere. Smartphone, tablet, web, etc. I have an Adobe Acrobat subscription plus a photography plan from Adobe so I do get 1TB of storage included. I haven't hit my limit yet so I don't know what the price would be to purchase a higher tier of storage. It's on their website.
One disclaimer about LR CC, I use it to manage my photos, never to edit. So when I need to get a photo to ACR and PS I get it saved to my desktop and open it.
