Bubby - if I understand correctly, you want to copy and link your gallery image in a post, right? If so, here is how I do it.
I'm in microsoft edge so the wording but be slightly different but should be similar.
First steps:
I open two tabs, one for my GS gallery and the other with the forum thread I want to post my layout in. In the gallery, open layout, hover over it and right click to bring up menu. Select "copy image" or "copy image link" or some similar kind of wording.
Go to the other open tab with the forum thread you want to post it in, in the reply box type
It's important to type
Now when you hit "reply" your image would be visible in the forum thread.
Next steps:
If you want to link your layout back to your gallery image, then you need to go back to the gallery tab you have open, highlight the URL at the top and right click to open menu and select "copy".
Then go back to your forum thread tab and if you had already hit "reply" then you need to select "edit post" at the bottom of your reply to open it back up. Then you highlight your image by holding down mouse key and dragging overtop of the image to highlight it or another way is to select the "go advanced" tab at the bottom of the edit box and click the a/A icon which is the first icon on the left side, then you'll see the code i.e.
and highlight that. Either way, it will highlight your image and then you select the link icon at the top of the edit box (5th from the right of all the icons) and paste the copied url in the box and select OK to save your changes.
OR A MUCH EASIER THING TO DO IS JUST TO COPY THAT URL and paste it below your image.
It sounds like a lot of steps but it quickly becomes second nature and only takes a few seconds to do. Hope this makes sense for you.