The file upload system is shit.
You can try drag-and-dropping the files directly onto the "Upload a file" area (the faint dashed rectangle below where you type your post), sometimes this works better.
If all else fails you'd need to upload your files to an image host.
I am trying to upload some of of my photos. Ive been trying pretty hard to use my 35mm camera and trying not to fuck up the film or shots.
Im using a OM-10 with the standard 50mm F1.8 lens.
Edit: how the hell do you do this by using files of your laptop. I have been using the "upload a file" tab and it is not working.