Sideways Pics

And earlier I found that all the pics Sara had taken on her phone were presenting themselves sideways. They looked upright in Irfanview, which I use most of the time, but not in a web browser so I was panicking a bit. I looked thru other progs to look at the pics, then when I opened the pic in Gimp it said "Want to put the pic the right way up?", put it right, and then tried to save it in some obscure format. So I did that then used Irfanview to convert the obscure format to a jpg, this time a right way up one.

I don't know f. all about the uprightness and not of pics so if anyone has a clue drop me a line and I will hopefully learn