The iPhotos library should be okay, as is. My wife has had her's syncing up to Amazon Drive without any issues for quite some time now. Since iPhotos is such a sprawling
mess structure and it can change a lot when running, it can cause some substantial overhead and churn for odrive, so just keep that in mind.
Make sure you don't have auto unsync enabled, or the library might be unusable for iPhotos until you resync from the cloud
If you are using the unlimited photos subscription for Amazon Drive, you will end up with your videos attempting to upload and then being stuck in "not allowed". I would recommend springing for Amazon's unlimited storage, if you have the means, so that all of your stuff can go up.