If you have a monthly principal's message or school newsletter, create a page to host it. It is good to include a PDF version, as well as having the text on the page itself. DO NOT post an image (.png or .jpg) of your document, because it "looks cuter". That makes it inaccessible to screen readers. For ADA compliance all the information must be in some form of readable text. You can include a picture of your principal on the page, or a cute graphic if it is a newsletter.
If your principal or whoever is responsible for the newsletter will not be doing it monthly (or regularly), don't create a page for it. It looks bad when the current message is several months old.