Step 1) Find chart Step 2) Copy image location by right clicking like so: Step 3) Insert into post by clicking this icon Step 4) Profit!
I know this is an old thread but it looks like it never got answered. I use finviz.con and then just copy and paste the chart URL into a post and it is dynamic and updates every time a page is loaded.
Just an FYI, you can also simply copy and paste a picture into the textbox and it will automatically post the image for you. You don't have to upload to imgur, or clicking the picture icon above the textbox. I know @Tiptopptrader does this just like I do. EXTREMELY time efficient and easy. Just copy and paste the picture as if it is text.