Tip: If you give a Muncher tile custom graphics, it will still act like a coin when a silver P-switch is active, whether it looks like a coin or not. So make sure to use ExAnimation if there's a silver P-switch in the area.
I recently learned how to do ExAnimations thanks to the tutorial on this site. I managed to successfully make a 2-frame torch flame and a 4-frame waterfall. The problem is that, while the animations display correctly in Lunar Magic, they glitch in-game, reverting to the frames of the animation they replace. I'm not sure what I did wrong.
-------------------- "Fortunately, I have a delicate lock-picking technique" *blasts doors open*
-Optimus Prime - G1 - Day of the Machines
In order to have the animations work correctly the way you currently have them set up - by attempting to overwrite one of the game's original animations - you need to place your new animation into one of the predetermined slots which the original animation you're attempting to overwrite used (for LM1.7+ only - this trick is not possible in earlier versions of LM). The LM help file can help guide you as far as what slots you need to use under said circumstances. Otherwise, yes, do as Alcaro suggested, which is a whole lot easier.
Well, the better thing to do here is to set it to another 8x8 tile. To do that, press the red poison mushroom () and click the bottom dropbox. It should say "AN2: 7F Skip File". Click it and find the number of the ExGFX file you used for the animation. Open up the 8x8 tile map editor () and press Ctrl, Shift, and Page Down at the same time. Press the down arrow to go to the 6th page. ExAnimate the tiles from that page to and empty tile number on page 2.