I think when you are uploading from your computer to the board it will show a large thumbnail and then the actual photo as its normal large self. Try and delete the smaller file/pic and Preview it before you post. If your larger photo is still in the preview and the smaller one is gone then you are good to go and can post and not have 2 images.
Let me know how it works for you.
PS ... I still love this cool toy your made your Sweet Parakeet ... she was lucky to have been spoiled by you!