(scroll down for Flickr instructions)
Probably the easiest way to add an image to your post is to host that image on Imgur. You don't need an account to use it but I suggest making one (it's free) so you can have access to some more features and the photos you upload.
Step 1: Go to Imgur.com
Step 2: Click on the "Upload Images" button. Choose how you want to upload your photo to Imgur.
After you select how you want to upload, click start and up it goes!
Step 3: Copy the Direct Link
Once it finishes uploading, you'll get a screen with some image options. You are looking for the Direct Link to the image and it should start like this: http://i.imgur.com/xxxxxxxx
Copy that URL (you'll be pasting that into the Forum).
Step 4: Paste into image dialog box on forum.
On the Forum side, click the image box and past in the URL you just copied.
This is what it should look like once you paste and hit publish:
You'll notice that in most cases, the original image will take over most of the screen. If you want to embed a smaller version, you can select a different size option on Imgur. Selecting "Large Thumbnail" (or any size) will change the URL's for the image and you'll just copy the direct link the same way you did earlier.
You can see how a smaller image may work best in some cases.
Step 1: Log in to Flickr
You can also upload your photo to Photobucket or Minus or any other number of places and link to it that way. The process is similar to Imgur's but a little more involved.
You find the image you want to use on the Internet, right click, select "Copy Image Location" and then paste it into your forum post (using the "Insert/edit image" tool).
Go out and add some color to your posts!
I edited this to make it easier to follow thanks to a guide I found on The Verge.
Edited by mikejulietpapa, 03 April 2014 - 10:25 AM.
Updated Information / Process