This applies to uploading pictures from your own computer, please ensure you have made them as small as possible first, see general post re posting pictures for guidance if unsure.
Then when posting click
'Additional Options' and you'll see a button marked
Browse, simply click button and navigate to the picture file on your own PC and click on it, if you click on the bit I've arrowed in the picture below you can add up to 4 pictures but the total
musn't exceed 192kb
Example of four pictures uploaded from my PC below