Board Thread:Questions and Answers/@comment-28125426-20161227063847

So I've only been sourcing my images from scans of my physical copies to date, but since some issues are too old to provide clean images I bought my first digital issues to source them.

Long story short, I've taken screen shots which automatically provide .png format images. I want to keep everyone happy and stick to the preferred .jpg formate but just renaming it such rejects the upload with this message:

File extension ".jpg" does not match the detected MIME type of the file (image/png).

Can someone please explain to a computer novice how I can change the format (on Mac) so it will accept it as .jpg? Thanks. 