how to put the the image of the render
The thumbnail is the first image you have attached to the first post of the thread
Let’s start with the question. Are you asking how to make your image show as the thread thumbnail for a thread of yours in the Artwork forums, or are you just trying to figure out how to attach any image to a post?
Open the first post of your thread attach the image you want to use as the thumbnail. To attach the image use the ‘insert image’ button. You can have more then one attached image so the thumbnail is the first one.