Alternately, to post multiple pictures at the same time to your Wall: open your FB app. At the bottom is a blue bar with "photo". Tap that.
It opens a window with ALL of your pictures, newest (by modify date) on top. Tap as many as you like to select, then tap DONE and it will upload all of them in a single post.
If you want to change to a specific folder in your DCIM, look at the top left. It should say: "All Photos and Videos, Tap to change". Tap. It will give you a list of folders. If you just took the picture, choose Camera. It will give you a grid of pictures, and you can select as above.
To paste to a SPECIFIC PAGE, you must go to that page in your FB app, and post from that page.