First of all you need to 'host' the image somewhere. I have been using postimage.org without problems.
Then, when you are posting to the Bar & Grill, look at the buttons above the section where you type.
Look at the second row of buttons, and hold the mouse over the second one from the left. You will see the text 'Insert Image'. Click that button, and two sets of square brackets will appear with 'img' in each one. Paste the address of your picture between the two sets of brackets.
So, it will look something like this … [ IMG ] paste your picture address here [ /IMG ]
To post a picture or image, the pic or image must have a http address.
Pics on the internet already have a unique http address but if they don’t work, it could be a copyright issue.
You can either search the internet for a similar pic that works, or take a screen shot and give it a http address yourself.
Both are easy to do.
Use Lightshot to take screenshots. Its user friendly and free.