Click on reply, then on additional options, then click on browse, and choose the picture on your computer you want to put on here. They can't be bigger than 126 kb so you'll need to reduce the size first - Microsoft Office Picture Manager can do it, but you will have a similar programme, open photo in that programme and click on edit pictures then on compress picture and choose web pages, then save as and give it a new name to avoid reducing your original picture. Then you can upload it on here as above, and click post. Job done. Here is my wet light Sussex Cockerel, Jamie!