Click that button once and a small window opens. At the base of the small window on the right are the words "Basic Uploader" This will give you a single browse window at a time to upload your photograph. If you have more than one photo, you can hit the plus mark and add an additional field. Uploading one image at a time might be quicker for your connection.
If your file is too large, the system will give you a notice.
Give it another try and let me know how it goes. I will attach a large 700x700 image to this post as a test.