Why are my downloaded photos not showing available when I try to upload them to Facebook?

A

AC Question

I have a lot of downloaded photos of items i sell and i'm trying to upload them to a facebook party i'm having but when i go to add images it's showing a black box with the circle and a line through it. But the images are there if i go to my downloaded image folder. How can i fix this? I really need to be able to upload photos from my phone.