Unfortuneately some of the images go off screen so until that gets fixed this is the best I can do
1. Imgur - http://imgur.com/
2. Tinypic - http://tinypic.com/
3. Imagebam - http://www.imagebam.com/
4. Photobucket - http://photobucket.com/
5. Bayimg (untested site) - http://bayimg.com/
6. Pixxx (untested site) - http://pixxx.me/I/index.php
Now, find the picture you want to upload, then go to imgur.com. Once you're there click the button the red arrows are pointing to in the image below
After that, a box will appear. Choose how you would like to upload it(if it's a picture you found online, paste the image url in the top right box. if it's an image from your computer click the top left one).
If you clicked "browse your computer" a window like this should pop up. Now, go through to where the picture you want to upload is located and then double click it. After that, click "Start Upload"
Now you should be on this screen. What you want to do now is copy the BBCode link(shown by the red rectangle and arrows). To do that left click it, then right click and click copy.
Come back to the forums and navigate to where you want to upload the picture(in this example it will be in a regular post) and paste it. To paste it either press Ctrl+V on your keyboard or right click the post and click "paste". That's it.
.