As an alternative to snow balls suggestion, here is how I upload pictures without external applications.

1. Take the picture with your regular camera on a phone.
2. Transfer to google drive; I think most people have a google account.*
3. Set the image to be available to anyone who has the link, rather than restricted.
4. Put the link in your post.

*For those without a google account and for those who want picture embedded itself.
1. Take the picture with your regular camera on a phone.
2. Visit https://imgbb.com
3. Upload your image and select "Don't autodelete".
4. Change embed codes to "BBCode full linked".
5. Paste the result into your post.

For example, here is a picture of a harmony chart for the major tonality.
<url=https://ibb.co/HrBvpXT><img>https://i.ibb.co/7GjcNbt/Tonal-Harmony-Major-1.png</img></url> *
* The < and > should be [ and ] respectively; I have changed them so that you can see the formatting.