Originally Posted by canklecat

To upload from an online host you'd need to click on the "From URL" box rather than upload from computer. Choose the "copy image address" rather than the URL for the entire page on which the photo is hosted. And it may be necessary to check or uncheck the "Retrieve remote file and reference locally" option.

Here's one of my photos hosted on Google Photos. I find it easier than Photobucket, Flickr, etc., because I can right-click from Windows Explorer or elsewhere and upload directly to Google Photos without having to log into yet another file hosting service. The only catch is it's necessary to remain logged into the Google account pretty much full time, but I already do that anyway for cloud storage with Google, Amazon, iCloud, etc., anyway.