Test post from Flickr. This is not my Flickr account. I clicked on the Share button in their Set and then by adding in my website address and logging in, Flickr created a post in my blog with thumbnails from the Flickr set. The title of this blog post was the title of the Set from Flickr, but I changed it myself by going into WordPress.
On my personal website I use the Flickr photostream widget that displays the most recent upload. However, this is a good way to bring in other images.
For Instagram , wordpress has a widget (widgets are in dashboard under “Appearance”) so you can place a stream from Instagram on a sidebar or footer area. The embed and URL options don’t seem to actually work in the WordPress blog.