As the others above said, you might just have uploaded a sideways picture. To fix this, you'll need to use an image editor of some kind to flip it on to it's correct side. If you do not know how to do this, or do not have an image editor on your computer, I suggest using online sources such as: Lunapic.com
There might also be the option of using your computer's Paint program to do this if you can. Here are the steps to complete the task with Microsoft's Paint program...
Open Paint either by finding it in your programs bar via "Start" or by inputting the word Paint into your search bar after clicking "Start"
Go to the "File" or "Blue button" and click it, then click open
Open the image you want to fix
At the top bar, near the options such as "select" and so on, should be a button called Rotate
Click Rotate, and then click the direction you want until your picture is where you want it to be
Go back to file, and click save as...
Save the image, and then upload it as your new SoM Avatar
If you decide to use Lunapic but do not know how to use it, here are some steps to do so...
Click on the browse button
Open the image that's sideways (Your avatar image)
It will load, and afterwards, you'll see a variety of options; Hove over the "Edit" tab under Lunapic'stitle image
The second-to-last editing option should be seen as "Rotate"; Click that, please
After it loads, you'll see a scroll bar and two arrows; Click the right or left green arrow until your picture is facing the way you want it too
After that, click on the image and click "Save as..."
Save the image, and then re-upload it as your SoM Avatar
If you follow those directions, you should have a normal picture.
Hope this cleared up any other confusion you might have had. Have a blessed day!
I hope this isn't spam but I forgot to mention a few things that might also be helpful to you. First, the picture requirements state that the picture itself can only be a .jpg or .gif - if it is not either of those two, then uploading problems may occur. Also, if it is a very large picture pixel wise then uploading problems may occur as well. Also, having a different source for the picture (example: Saving it from Lunapic or Microsoft's Paint) might fix it too, as sometimes it might just be a source issue. That all being said, I hope you find out how to fix it soon!
Note: If the picture isn't too important, you could always try uploading a new one to see if the same thing happens.