My digital camera uses Nimh recharable batteries from factory 1600mah does it matter if i use 2500mah?

Not only is it fine, 2500 will give you more shots before you have to recharge. The camera will use the power it needs, and will not draw out any more then what it needs to take the picture (which doesn't change depending on the battery). And you can think of it sort of like a bucket of water, and the 2500 is a bigger bucket then the 1600.

nope.

2200, 2400, all fine.

Yes, it's much better to use the 2500mAh batteries. They will provide you with a lot more power than 1600mAh...the higher the number, the longer the battery life.

you should use the 2500
they will last almost twice as long.
they also have 2700 and 2900's.
I mostly use the 2700's

The higher the mah is the longer the battery will last...

It was a good move to get a higher rated battery