Unless you can tell us step by step what you are doing, it will be impossible to give you any advice.
Start with ...
Plug the camera into the computer/laptop using a USB cable.
Turn the camera ON so the computer will recognize the device. It will then open a window.
The window says "checking for duplicates"
Then it says "Uploading photos" and show a file or a list of images. with the date you uploaded them.
Then they are stored on your pc or laptop in a photo program or in My Documents and My Photos.
Then when you post a reply, you click on Manage Attachments and it opens a window. The window says "BROWSE"
It asks where do you want to look for the photos AND this is important ..on the desktop? on a photo program? in My Photos etc.
You have to open that file or list by selecting it and "OPEN" Then it shows all your recent photos.
You select one at a time and UPLOAD each one.to a maximum of 4.You must wait while they all UPLOAD and it will show that.
They are now part of your reply and they should all show up....
Your process should be similar based on your camera and your computer., so tell us how you are trying to do it...