Sorry cam, forgot you were on iPad. Above works for iPhone. 
For iPad Photobucket App:
Tap Photobucket App on ipad----->Photobucket front page should come up------->probably default to 'Find Stuff (bottom left)---->tap lower middle button (My Albums)------>tap arrow pointing up in upper right hand corner -------->choose upload source (photo library)------>tap camera roll------>select photo-------->when you tap this a box on the left says 'processing' -------->in 'My Album' tap photo ------>tap chain icon (upper right menu)------->tap IMG code------> it should say 'Copied'------>go to OOF and open new topic or open reply, depending on what you want to do----->tap in reply box/new topic box or whatever until 'Select/Select All/Paste' option appears on screen----->tap 'Paste' option----->go to 'Preview' and your photo should be there on screen. Type message as normal and jobs a goodun as they say. 
Hope that makes sense. 
Regards
Alan
Tried again, ok, so I've copied the image to clipboard in photobucket...opened a new topic in th OOF gallery......you then say to tap the new topic until select/select/all/paste comes up? It doesn't.
As its a new topic there's no reply button yet, and there's no select/paste option that I can see? Have I followed your instructions correctly??
Really sorry to be a pain, bugging the life outa me that I can't get pics up, and that the world and his wife seem to be able to without a problem.... Leaving me feeling very inadequate that I can't. Story of my life!!

Right, let's take it a step at a time.

I'm determined as well now.

Have you got to the stage where you can tap the IMG link in Photobucket app and it says 'copied'?
If you have, you can either practice in 'Test Area' or open 'New Topic' in Gallery section if that's where you want to post the image.
As far as the forum part goes, open new topic, write in the new topic box 'My New Car' or whatever, go to the large reply box below (where you normally type your replies), tap the screen in that box and I would expect to see select/select all/paste. If not, we'll try to find out at what stage it's going wrong.

Regards
Alan