Rick I would like to see you add some additional data to this post. Bo had a very concise post in the Platinum forum on how to like a forum post to your gallery. It precludes having to resize a gallery image and uses the auto generated medium sized photo in the gallery for posting to the forum. I myself use the following method for all my posts which allows members to click directly on my medium sized post and then be taken directly to the larger image in my gallery:
Upload your image to the gallery as normal, by clicking on upload photo to gallery. follow the directions to add your photo and shooting data and comments. Once image has been uploaded, Go to the image and open the largest size. While still in the gallery open a second window to the forum you want to post in. Click post in the forum menu to open an upload window. Enter your text or do as I do and copy your text from the gallery in the forum window. Now go back to the Gallery and copy the link in your browser that links to your large image and paste that into the forum window just below the text you added. Now right after that pasted link place a "|". Now go back to the Gallery and click on your image to get the medium size display and copy the link from the box below the image and paste it in the forum window right after the "|". Add a "]" after the end of that link. While still in the forum window, go to the front of the link and remove everything from the first link you copied up to "Nikonians" and replace it with "[link:www.". Next add the following right after "Nikonians" "-images". Now move to the second copied link and make sure the start of that link says "http://www.nikonians-images". Below this link add the following text "click image for larger gallery image". Spell check your entry. do a preview to make sure the image displays and links to the gallery when clicked, and finally upload.