Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I use iCloud to store my photos so they are available on all my Apple devices but I also use Google Photos to back up the same information. I tend to switch devices a lot so this ensures all my Android photos are saved too.
 
Personally I use dropbox. Not only its desktop client is super reliable (more so than Google's), it is supported by Office as online storage.

The draw of Google Photos is the free unlimited storage, but it recompresses your photos, even if it is under 16MP. Just try it. A normal 8-16MP is probably a few megabytes. After being "backed up" to Google Photos, it becomes a couple hundred kilobytes. So the free unlimited is really only for super casual users. Once you opted for the full res that is counted against your storage, then flickr is a better deal (1TB for free).
 
I use both--but only because Google Photos doesn't support Live Photos...yet. I'm hoping that Google Photos will soon support Live Photos, and when that happens, I'll probably dump the iCloud photo library.
 
But I do like all those special things Google Photos can do to a dump of pictures, gifs, movies, touch ups!
Then it's fine. Most people would upload their pictures to social media that would resize, recompress, and even "retouch" them anyway.

For me though, I was looking for more of a real backup/archiving solution, and I was expecting a service offering photo storage would, at the base, an archival solution (they can add on the fancy features on top, but the baseline should be proper backup). I thought that the free service would at least keep the photos intact if they are below 16MP (even the 6S is only at 12MP, and I was using the iPhone 5 which is only 8MP). But I was mistaken. Hence flickr's offering of 1TB free is a better deal to me for photos than Google's 15GB.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.