Another way to post a picture is to simply make it your profile photo. We won’t be able to see details so well, but seeing as the idea is to look at your overall shape, not an outfit, that’s fine.
My take on body shapes is this: they are general types, intended to quickly convey a rough idea of shape. As Joy said, most of us won’t fit any one of them exactly. So people decide which ones they think they are close to and start trying on items suggested for that shape, deciding as they go which ones work for their specific body.
You can do that even without having a lock on the shape. If you think you are A or B or whatever, go read up on suggested styles. Try the ones for which the reasons appeal to you. If there’s a style that supposedly takes emphasis off your shoulders and you are happy to have yours be big and square, then skip that tip. If it’s never occurred to you that the shape/length of your neck is a problem, then don’t worry about it—it isn’t. If you find yourself nodding in agreement as you read through the reasons for recommendations for a certain shape—minimize this, highlight that, then you’ve found the shape guidelines that will work for you. This also works if you don’t agree with the body type the fashion gods have deemed is what we should all try to emulate. For example, I’d much rather have some junk in the trunk, so I ignore anything about deemphasizing my rear.
A fun way to do this is to go to the mall and line up a few pieces for the shapes you think might fit your shape, then go to town. Have fun. Love the ones that work, laugh at the ones that don’t. Enjoy!
