I'm not sure if you not how to enhance the size or not but I'll enlighten you. I do Cltrl + Alt + PrtScn and then I go into paint. Then there should be an option in the top left hand corner saying paste. Click that. Once done simply differ the size to your liking. Save the picture in your documents. Then when posting click Host an image. Select the file from your documents and click host, you should get three different URL's. Copy the bottom one and click on the button next to it called Image. Paste the URL and then you're good to go.