So if I multiply the 62 numbers together, would that work?
But if I add them together , won't that create a very weak key, a small number that is still in the range of computers that go through addresses 1 by 1? So isn't it important to have the key at the higher ends of the randomness.
No, multiplying the numbers would destroy the informational entropy, you should string them together and take a hash of the string (SHA3-256 for example).
Perhaps take a photograph of the dice and then calculate the SHA-256 hash of the photo file?
That would depend on the randomness of the picture, and how random the bits are in the picture, which might not be that random.
Since the photo is of the dice, and the dice are random, then the values and arrangement of the dice in the photo would be random. Therefore, the entropy in the photo should be significantly higher than the entropy of the dice values themselves (since values of the photo would also take into consideration the location and orientation of the dice as well as the background).
Of course that assumes that the photo has enough detail and clarity to make out the values of all the dice.