Hello, Rachael!
As a matter of fact, I just had my own picture with Eeyore and Piglet taken yesterday at a wonderful character dining experience at
The Crystal Palace, in Magic Kingdom! This is my favorite location to meet and greet the characters over what's always a delicious meal, be it breakfast, lunch or dinner. You can linger over your meal as Winnie the Pooh, Piglet, Eeyore and Tigger make their rounds from table to table, hugging, kissing and bouncing their way from one group of fans to the next. It's always a fun meal for everyone.
Should you wish to see Eeyore and Piglet outside of a restaurant setting, you can do so over at the newly-refurbished queue-area for The Many Adventures of Winnie the Pooh. The new character meet-and-greet location looks great, and is just to the left of the attraction queue (if the Fantasyland expansion is behind you and you are looking at the Pooh attraction.)
Another favorite, often overlooked location for these characters is over in
Disney's Animal Kingdom. If you take a look at the map I linked, you'll find Mickey's classic hand icon as a marker for where Guests can meet their favorite characters. We always find Pooh and his friends at the one that's just before the bridge to / from DinoLand, U.S.A. Because this one is tucked out of the way a bit, down a path and behind a building, folks often miss it. Be sure not to, because it's a great place to capture a wonderful moment with Eeyore and Piglet!
Send more questions as you think of them! We love to help!