Unfortunately, I am finding on our site https://www.kingstoncarers.org.uk/ it is not possible to add additional images. They say they are uploading but do not show in the photo picker for main images on news items or pages. 

Strange, I can't reproduce this problem. I added a test image to the assets library on your site then was able to see it in the list if I went to your news page and clicked the Select Image button.

Do the images you uploaded show if you navigate to the Assets Library in the admin pages?

Thanks

Joe