the original battery for my Canon A4000IS camera is an NB-11L and states it's 680mAh while the replacement you show has 900mAh. Both batteries show the same 3.6V. I'm wondering if the replacement battery you offer will work and not damage my camera where the mAh are different?
As long as the voltage is the same you will be okay. The mAh is the total capacity of the battery, so a battery with 900mAh will run for longer than a battery with only 680mAh. Typically, and the more mAh the larger the battery, but if it says it is compatible you should be fine.