Ok, two things then;
1. I think that you might need to contact the membership secretary and ask that your status be checked
2. how to attach files and photos depends I think upon your computer - I am using a MacBook Air so your method might be slightly different say on a Windows machine
a. add your photo or file to your computer
b. click add post as you have so far
c. type your message
d. go to the section which says "Upload attachment" and click 'Choose File'; you will be asked to select your photos; the name of the file will appear in the box which currently says 'no file selected'; click add the file; a little box will appear showing progress; when that finishes you will have the choice to add the file or 'place it into the text'.
e. To place the photo into the text move your curser to the point you want the file to be positioned and then click 'place it into the text'.
f. most times the original size of the photo is too large for the normal screen so you may have to resize it, I do this as a percentage of the original e.g. 50%.
Best I can do, unless somebody can give you improved advice
TTFN
Hugh.