New phone, same pics=new problem

[Idiot Savant]

Hi guys,

Well? I just got an iPhone 7 and I'm taking and loading pics as I've always done with the 5...that old way no longer works on the 7.

That way was this: take original pics; crop and edit; send pics to my cousin then re-take the pics; crop and load them to this site. Worked perfectly!

Now I'm getting a whole bunch of red words telling me " Image file type mismatch: expected extension jpeg but extension png given"

What does that mean?