Here's what I do (Windows, but I don't think that is significant):
After Posting the reply in my thread, right click on the number top right of the newly posted reply (#61 for your latest image), click Copy Link Address
Write your reply in the main thread, and click on the Insert Link icon (chain symbol in the line of icons in the edit section). Right click in the URL box and click Paste, Enter some text in the Text box. Click Insert. Example link to your latest image is below.
Linky
Finish writing your entry and insert the image and click Post Reply
I then test that the link takes me back to my personal thread.