I have often wondered about this, have asked the question at conferences, and never got a clear answer. If it is not OK, could I expect repercussions? Am I being pedantic?
That depends on the contract you signed with the previous publisher. Even if you never signed a contract, the publication constituted a contract. You may have (implicitly) granted the publisher the right of exploitation and now need permission to use your own work. However, it may also be that all rights of use have remained with you. This also depends on the copyright laws in the respective country.
Wolfgang Dick is correct. The easiest approach is to ask for permission at the publisher (often this can easily be done online) and most of the time you can freely use your own figure. Yet, exceptionally some publishers ask you to pay for your own figure. Don't : try to make a slight variation.