Willy and Sinker are spot on.
It's the way some devices now save images. Instead of taking them the way around you were holding the phone / camera, they save them horizontal with a bit of data (called EXIF data) that effectively says "display me rotated by x degrees".
Then when uploaded to some sites that cannot read the EXIF data, like AditNow they appear on their side. eBay sometimes falls foul of it too; that's why you occasionally see an upside down car...
Solution - open in something and use Save As to save a copy without the EXIF data. Microsoft Paint strips all the data if you have access to it. Or open in Photoshop or similar, and copy and paste to a new image of the same size.
Bit of a faff I know, but the coding to allow image rotation either before or after upload is too time consuming for me to implement at the moment. Unless there's a mine exploring millionaire out there who wants to pay for it :lol:
my orders are to sit here and watch the world go by