Sign up and upload your photos to your album:
Select: 'Reduce to Medium' and 'Choose Files' or use 'Bulk Uploader'
When the images are loaded into your account, you will notice when you hover over them codes will appear under the image. If you highlight and copy the 'HTML code' then paste that code into your forum post your image will be visible (once you hit save/add discussion/reply to post) for all to see.
Here is a slideshow I made in photobucket from one of the Kombi get togethers we went to on Australia Day.