Why can't I download photos from email or web onto the phone?

I've been trying to load a page of Google Photos on my phone from a link that a friend sent me by email. The photos -- even thumbnails -- do not load. So I opened the page on a computer and downloaded a photo I'd like to have on my phone and sent it to myself by email, and the phone won't download it. It acts for a while like it's downloading and then just stops and nothing happens. No error message, and no photo. I tried shrinking the file size on the computer and sending it again -- still doesn't download. Anyone know how to help? Thanks.