Adding Roll20-modified published content to forum - is that a legal issue?

Hey folks, I'm new to Roll20 (at least as a DM) and my group is playing World's Largest Dungeon (AEG, uses 3.X rules, etc). I have been gradually loading "player" version of the poster sized "region" maps into Roll20, adding dynamic lighting and some tokens to match the book's room descriptions, etc. I am still early in the process, but it's a LOT of work. I know folks are curious about WLD even though it is frequently criticized for having some major typos, inconsistencies and playability issues. I was thinking of posting the finished products somewhere, and wonder if I could get into trouble for doing that? If not, where would be the appropriate place to send/post the maps? If this is a stupid idea or something, just let me know. I'm just thinking this is a ton of work to just sit on and not share, and may help other GMs realize a bucket list goal of running WLD! Thanks, Matt

I'm not familiar with WLD or any of those things you are talking about, but if you are using copyrighted maps, I'd advise against publishing your modification publicly unless the original license explicitly allows for that.  Check the license or contact the copyright holder directly, first before you do anything.

Sounds good, fellas. Thanks for the quick replies! Incidentally, if I am able to get the rights, can I somehow save the maps and share them with the dynamic lighting in place?