If you click on "New Reply" you'll go to a page that has more options than the "Quick Reply".
In this page you'll be able to add attachments, but notice that you have a size limit for attachments that you can add in this forum.
What I do, and what I see as best solution, is to upload your image to imgur, postimg or some other image hosting site, and then use [img]someurl.png[/img] in your post.
And if you want to do even better and post a small size of the image with it enlarging upon clicking (as I've done), you can do the following:
[url=bigimg.png]
[img]smallimg.png[/img]
[/url]
In this page you'll be able to add attachments, but notice that you have a size limit for attachments that you can add in this forum.
What I do, and what I see as best solution, is to upload your image to imgur, postimg or some other image hosting site, and then use [img]someurl.png[/img] in your post.
And if you want to do even better and post a small size of the image with it enlarging upon clicking (as I've done), you can do the following:
[url=bigimg.png]
[img]smallimg.png[/img]
[/url]