Search:

Put that link in the box you get when you click on the little image icon which is above the text box you type in.

https://www.flickr.com/photos/cloud9doula/12729892733/in/photostream/

https://flic.kr/p/qq9ijJ

https://www.flickr.com/photos/cloud9doula/12729892733/in/photostream/

https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xap1/t31.0-8/p600x600/10749909_10154897518380697_699877018429689057_o.jpg
...

Flickr is the second best option.

Photobucket is the easiest to use.

Yes. I have to post them somewhere else then put the link in the URL place on the photo uploader and also have to uncheck that box that says "Retrieve remote file and reference locally".