This is a bit of a process for newbies, but once you get used to it, it's not so bad... First, if you do not see an icon above the text box that looks like a paperclip, click select "Go Advanced" from the buttons at the bottom of the text box.
Skoolie Photo Upload 1.png
Then, select the "Attachments" icon (looks like a paper clip).
Skoolie Photo Upload 2.png
This will bring up the attachments management window, from which you can select "Browse"...
Skoolie Photo Upload 3.png
Which will open a window from which to select the folder the file you want to upload is in, and which file. You can then select "Upload"...
Skoolie Photo Upload 4.png
When your file has uploaded, the file name will disappear from the "Browse" button and its name will be displayed below the "Upload" button... Now select "Close this window"...
Skoolie Photo Upload 5.png
Select the "Attachments" (paper clip icon) again. It should now give you an option to insert the file you have uploaded. Be careful not to modify or delete the [ATTACH] xxxx.sss [/ATTACH] code.
Skoolie Photo Upload 6.png
VOILA! Your photo is now embedded in the post. All you have to do is select "Save Changes".
Skoolie Photo Upload 7.png
Alternately, if you want to share an image from a URL (web link), there is another icon that looks like a picture. This icon will bring up a box into which you can paste or type the link to the image you want to share. It works for YouTube videos and such as well.