You cannot upload files using the web-based upload UI, if you use an iPad, as it does not let you choose files from "disk" etc. However methods like Upload by email to get photos onto the site from your iPad or phone should work. Otherwise a Windows PC does work.

At the side of your own personal id there is a drop down menu, click on add photos, another page appears where you can either add multiple photos or single photos from your computer files when you have chosen your picture/pictures, then you need to click on the button below where you have been which says add photo. This should then add them to your own personal page if that is where you want them. If you want to add them to a question there is a button which says add photo, same method applies and if you wish to add them to a blog it is more or less the same method but it does take a while to download pictures you must not navigate away or leave the page until they have been downloaded otherwise they will not download. I took ages to understand it when I first used it but practice makes perfect. Hope this helps.