This may seem a little confusing at first but after you do it once you'll have no problems and will love the ability to share pictures of your planes and adventures, which we highly encourage you to do. So, here it is, step by step:

1. Get your photos on the internet.
There are several free hosting sites out there.  Some of the more popular ones are:
photobucket.com (need to sign up for free account)
imageshack.us
tinypic.com

While uploading, make sure that you select 'resize image to 640x480' otherwise your 6mp photo will overfill the screen and take forever to load when someone tries to view it.  One the other end of the spectrum, please don't display thumbnails as they are too small to view and require the viewer to click on them to see the whole photo.

2. Put a link to your photo in your skiplane.org post. 
You are only looking for a DIRECT LINK to the photo itself, not a seperate webpage or the thumbnail.  The hosting site will give you several different options for links.  The link you are looking for should end with .jpg

Click on the "Insert Image' button and insert the link between the code that pops up.

Your photo will magically appear in your message.