I am only familiar with photobucket so this is what I will use to show you guys how to do this.

Step one, Go to http://www.photobucket.com and register (Assuming you're looking at this, I assume you're new to this sort of thing)

Step two, Select the upload button:

upload desired pictures and finally.
Step Three, Copy the IMG code:

Paste here.

How to Hotlink a picture: Right click the image and click "Copy Image Location, then put [IMG] in front of the image link and [/IMG] after the image link, and it should appear.

**NOTE: Some sites have an anti hotlinking feature, so becareful haha wouldnt want an error message showing up.**