Thanks for all the feedback. I've tested creating folders and that is the answer to my problem. The camera lets you automatically create a new folder every day. Therefore the next time I go on vacation I'll just set the camera to create a new fold...
Great idea about folders! I think that may be the solution. I just created a second folder. The first folder was 100canon and the second folder is named 101canon. I'll start adding pictures when i get some time and see if I get 255 in each folder...
I'm using a Dell windows 8.1 computer. I have transferred the pictures by removing the card and having it inserted into the card reader slot. I also transferred the pictures by using the USB cable. The same result. Only 255 pictures appear.