First and Foremost , A warm welcome to Mp , Its nice to have you here . We are sorry for the inconvinence cause to you , We will surely help you out.
Do read the : Newbies pictorial guide to MP:
You will have a demonstration on how to post with images.
To be specific, Firstly you have to make a new thread in the appropriate section.
Then fill in the details ie. the subject , the body , and in the latter part of the window , you will see the attachments option , Click there and select the file .
Do read the above link i mentioned , I hope this solves your doubt, If you still have trouble do post in again , we will make sure will help you futher more.
Thankyou and Regards.