I am on a school laptop that everyone has. But, we are not able to use the preview button. Is there some other way to make photos (That I downloaded from Facebook) into a JPEG. I need it for a Weebly assignment.

It is more than likley already a .jpg file select the file and do a "Get info" to see the extension. If it is not you can convert it at Zamzar - convert document, eBook, image, audio and video - free online file conversion

Where is the saved file? OS? Right click open with "mspaint"? Need more info