Cool pics Erkwin! Thanks for sharing.
To put pictures directly in your post, click the button "Insert and Image" (top left, when you write a new post). Then you will be prompted to upload your image (= host it) on www.servimg.com.
Do that. Once the uplod is finished, the website gives you a bunch of "codes".
You need the BBcode
for the image
(not the "thumbnail-code"). Just copy/paste it into your post and done!