You don't go to the advanced setting first.....you search for your pick first....
Then the box comes up that says, Add an image...the ( computer box is not highlighted in green like the URL box - but you can still click on it. Then hit select files at the bottom....get your picture and then upload it.
Once you have you small thumbnail pic....put your cursor over the pic...and the pencil will appear in the left top corner. When you click on it opens a box
that says image setting. Click large or full size and then save at the bottom.
In order to preview at the bottom right hand corner, click 'Go Advanced' preview pic and it must appear larger or you have not done the steps right.
Then submit...

Easy as One, Two...Three ....