To post pics, here's my method.
First size your pic, I use 1280x720 pix.
In the reply area, click on "Go Advanced".
At the top row of icons, left end, there's a blue A, click on that turning off the blue.
Place your cursor where you want the pic to be placed. I usually use a couple lines below my last comment.
Then in the second row of icons, fourth from the right, is a square pic with black dots at the corners, click on that.
A small screen appears, I select "from computer", then click on "browse".
This allows you to search for the pic you want from your computer database.
Find that pic, click on it, then click on "open".
Then click on "upload"
Depending on your computer speed this might take a couple seconds to several and the pic will show up where you placed your cursor.
If you want the pic to be larger, double click on it.
This will open another window and you can choose the size you desire. I use full size.
Now your pic is posted at the size you want, click on "submit reply" at the bottom right.
Your result will look something like this.