1. Go to %appdata%/roaming/ 2. Go to .minecraft folder 3. Go to screenshots 4. Find the screenshot you want 5. Put it somewhere convienent, like on your desktop. 6. On the forums click "Upload a File" (Its beside the Post Reply button.) 7. Find the picture on your desktop and wait for it to upload. 8. You should see the screenshot under the Post Reply box. Click post as picture. 9. You should see the screenshot in the Post Reply box. Go ahead and hit "Post Reply." 10. DO THA STANKY LEGG 10xxx. You could also upload the picture on a picture sharing website. Once done, right click the picture and select "copy image url" 10xxx2. Go to the Post Reply box and type 10xxx3. In between the two brackets in the middle paste the image url there.