For Jannxin,
Not everybody has their Quick reply box with the tree image (this is a setting that you customize- and it took me a very long time to find it).
there is another way
when you reply to a topic and want to upload a picture, click on the Go Advanced blue button. Once in that prompt, about 3/4 way down the page is a button that says Manage Attachments. Click on that. Then browse to pull the photo from your documents, click on upload, and wait for it to upload. then close the window, and Submit your reply.
If you want to start a topic and post a picture, everything is the same except you won't need to start out by clicking on the Go Advanced button.