browsing for photos

Since getting a new iMac with Yosemite and the horrid new Photos app, I am unable to browse through my photos from facebook or any other website where I might want to upload a pic. All I can see are folders and folders, but no picture thumbnails. Help?

1. iPhoto has not gone anywhere.

2. Photos is almost identical to iPhoto. A new coat of paint and some nice new editing features (and a couple of things taken away), but essentially just iPhoto.

It sounds like the OP may have recently purchased a new iMac with the latest version of Yosemite that may not have included the older iPhoto app?

I am not sure I understand what you mean.
When you say you see folders and thumbnails ... could you share a screenshot ?
Maybe that will make things a little more clear..

Cheers ... McBie

You want "thumbnails" put Finder into column view. Click on a pic, see the preview next to it.