I am sure someone will come along and show the link (Britman did the last time) but here is a short "story" on how it should work.
The website I use is
https://postimg.ccI don't know if you have to set up an account but I did.
Once you have access, there is a button at the top of the screen that says "upload". You click on that and the program shows you a new page where you can look for your picture wherever you have it stored or, which is sometimes easier, have your browser up and not in "full screen" mode and have the file folder open such that you can see them both. Then all you have to do is to drag the file over to the "upload" area and it will be done.
After the upload is complete there will be a list of "Links". If I remember correctly the link for "forums" is the second one from the bottom.
You simple click on the copy link icon/thing and the link will be copied to your "clipboard".
Then you go to the forum where you want to put you message and "paste" it there. I use "Control V" (passing the control key, holding it down and then pressing the "V". The link will be pasted as needed.
Now, if you have read this far, I hope this does make some sense.
If not..... you can ask a question. Maybe I might be able to answer it.