Fuji cameras usa

DEAR FUJI,
WE WENT ON A TRIP AND USED A FUJI FINEPIX S1000F AND A CANON SUPER SHOT A3300is , THE FUJI IS 10 MP AND THE CANON IS 16 MP. AT ONE POINT THE CANON CHIP WAS FILLING UP FAST SO WE SWITCHED THE
CHIP FROM CANON TO FUJI SO I COULD GET MORE PICS ON WHAT WAS LEFT OF THAT CHIP. THEN BOUGHT
AN 8 GB CHIP FOR THE CANON. WOULD THAT SWITCH CAUSE US TO LOSE SOME PICS OR "HIDE THEM" ON THE CHIP SOMEHOW?? I DON'T KNOW MUCH ABOUT IT. ALSO IF THE FUJI GOT FULL AND I DIDN'T NOTICE, COULD IT OVERWRITE EXISTING PICS IF I KEPT SHOOTING THEM. MY PAPERWORK SAYS I SHOULD GET ABOUT 1600 PICS ON A 4GB CHIP, I AM SURE I SAW THE NUMBER OF 1669 AT ONE POINT. THAT IS WHEN I DECIDED
THAT I SHOULD CHANGE CHIPS. WHEN WE GOT HOME WE HAVE A NUMBER OF PICS WE CAN'T FIND.
IT IS HARD TO REMEMBER JUST WHICH CAMERA WE WERE USING AND AT WHAT TIME. WE ARE AT A LOSS TO
FIGURE OUT WHERE THEY WENT.
NOW MOST OF THE PICS WE LOST WERE VIEWED ON A TV TYPE MACHINE TO SEE WHAT WE TOOK THAT
DAY. THIS WAS DONE EACH DAY, SO WE KNOW WE TOOK THEM AND THEY CAME OUT WELL. WE DID THIS
TO MOST OF THE MISSING BUT NOT ALL. AND A LOT OF THE ONES WE STILL HAVE WERE VIEWED ALSO IN THE
SAME WAY. PEOPLE TELL ME THERE IS SUPPOSE TO BE AN INTERNAL CHIP SPACE ON THE FUJI BUT I CAN'T FIND ANY REFERENCE TO THAT IN WHAT PAPERS I HAVE ON THE CAMERA. ALSO THE FUJI IWTH THE 1669 PICS THAT WE LOST MOST THE PICS WAS FULL BEFORE WE SWITCHED THE CHIPS MENTIONED ABOVE.
CAN YOU HELP ME??? THANK YOU LEW REED