You have to load the photos into your photobucket account from your iPad/iPhone/digital camera.
The photos are stored on your photobucket account. You copy and paste the link to a given photo from your photobucket account to your post on a forum.
You can access your photos on your photobucket account via your PC/iPad/iPhone.
You can edit your photos for size, color, crop or whatever inside of your photobucket account if you wish....or load photos that you've edited elsewhere onto your photobucket account.
Review:
1) The photobucket account is the storage place for your pictures.
2) You can access your account via PC/iPhone/iPad.
3) While in your photobucket account, select the "direct link" to place a photo onto a post using the photo icon (from the left: world w/ chain link, envelope, washedout world w/ "x", photo icon to post pictures) on the tool bar on top of each post.
Wa la!