How many check images a member can view in online banking depends on two factors. The first factor is how long your item processor retains the images. The second factor, and the one most likely to be the limiting factor, is how long your credit union is configured to retain transactions for your draft (MEMBER2) accounts. Whichever of these two factors has the shorter timeframe determines how far back your members will be able to view check images via online banking.
There is no cap on how many checks can be viewed. As long as the checks were written within the available timeframes as detailed above, the images will be viewable online.