So I would like to post some of my artwork on the site and I know how to submit it and all that. Unfortunately, I have no idea how to make it change from a file on my computer to the screen (other than posting the link of my picture on some website, which I'd rather not do). Yeah. Help?
You can attach the pictures to your post. Down at the bottom of the post page, there's a tab titled "Upload attachment". Hit that, hit "Browse", find the image on your computer, and hit "Add this file". The page will refresh, and a list of attachments will appear right below the post editing area.
To put the picture in your post, scroll down to the picture in the attachments list and hit the "Place inline" button.