Wondering why your iPhone pics are upside down?
Turns out with the iOS software update to 5.x, when Apple introduced the feature of taking photos with the volume buttons, not just with the on screen button, the upside down photo can occur.
The phone is considered “up” when held such that the home button is either down or on the right. If you use the volume buttons as shutter release (with the home button on the left and volume buttons on the top), then you’re holding the phone essentially upside down. Snapping a photo in this orientation produces a photo that renders properly on some software but not on others (Gmail and Craigslist for instance). The photo is stored upside down in memory, but tagged for a 180° rotation, which Gmail and CL miss. Other apps correctly rotate the photo before displaying it.
So it’s a matter of Gmail and CL catching up and reading this meta data AND rotating the image appropriately.
Until then, remember to keep the home button down or to the right when taking an iPhone photo