The only way to correct the orientation is to open the pic in a photo editor and save it. That usually does the trick.
The issue is that this, and most, forums don't have the smarts to read the metadata embedded in the picture. That is what tells the orientation of the camera. Most photo editors do read the metadata and then re-orient the pic when you save it. Most, not all.
Gary, AKA "Gary fellow":
Profile
Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI