It has been written using Flickr - https://www.flickr.com - as the example photo hosting site but this is only one of many such sites and is not a recommendation as such, but it does seem to work pretty well...
So after signing-up for an account you need to upload the photos you want to post on this forum. Click here to upload

Once uploaded, click the photo you want to share then click the share button

Now select the option to share to a Bulletin Board , in this case 'BBcode'

Copy the link details and past then into your thread. You can shorten it to just the code between the "img" tags
"[ img]https://live.staticflickr.com/12345/1234512345b.jpg[/ img]"
If you're copying more than one image you'll find it easier to keep both the club forum and photo hosting sites open at the same time.
Does anybody else have recommendations for other photo hosting sites?