Add Image Shack to your 'bookmarks' or to your 'Favorites' list.
Open your Topic box and add your dialog, then click on your ImageShack Link in your Favorites list. Find the photo you want to add to your post and copy the 'Thumbnail' url code. Click on the back button to return to your opened Topic/Post box. You can either paste your 'Thumbnail' url directly to your post or you can click on the 'Icon' button located above the dialog box (button has two mountains and the sun on it) and follow the prompts. Click 'Preview' and view how your post will look-if you like the way things look click on the 'Submit' button, if not make your corrections then preview and submit.