Welcome to Pallet Town. Here are all the pictures you could want of Ash and Pikachu. Some together some separate.

Pikachu*
#1. Pikachu looking to the side
 #2. Pikachu looking depressed
 #3. Curious...
 #4. Pikachu with Japanese writing infront
#5. Relaxing in da pool
 #6. Staring at the water
 #7. Pi?
 #8. Anime sweatdrop
 #9. Determined
 #10. Ready to fight
 #11. Not sure what to say about this one. It's just cool.
Ash
#1. Ash just looking thrilled
 #2. Hey!
 #3. Ash is winning
 #4. Ash being confused
 #5. Walking out of the smoke
 #6. Getting his pokémon stolen by Mewtwo
 #7. From the opening (love dis picture)
 ASH AND PIKACHU
#1. From the Cellidon Gym
 #2. Aw... cute... ;-P
 #3. Hey, look!
 #4. I think they're excited about something...
#5. Let's go, Pikachu! (I like dis pic.)
 #6. Best friends
 #7. Peace
 #8. Yeah!
#9. Let's go!
 #10. You're a great singer Pikachu
 #11. Well, what now, Pikachu?
 #12. From Pikachu's Good-bye
 #13. Um... lunch.