Hi Choco! Looking forward to the pic!
Get a photo ready on your desktop first. It needs to be reduced in size to about 100 kilabytes say. Best to open the pic in something like microsoft office picture manager, and rather than compressing, change the actual size to about 30%.
Then, go to reply on the forum. At the bottom ,underneath "preview/submit" etc, you'll see "upload attachment" Click on that, then click on "browse" Select your pic, than press attach file. Then submit! sounds bad, but quite straightforward really.