You can edit the save file using a text editor. It can be a little hard to sort through but if you search for the MC's name you should be able to find it. It's recommended that you don't edit higher than 7 if you plan on using the lab. Values higher than 9 can cause strange things to happen.
If finding things on your own is too difficult might be easier to just an online editor, like say this one:
Don't check the box "both", that checks if there's an identically named body if selecting portrait, or identical portrait if selecting body, if no matching named one then it clears it. If you uncheck it(which i thought was the default), then it only sets the current.
Irfanview has a batch conversion option. Run it and select batch conversion/rename from the file menu.
This is only a warning, you can just ignore it... It doesn't break anything far as I can tell, just spams the console anytime they're loaded.
There's probably a processing option to save as png and preserve transparency, but png doesn't support layers far as I know. You don't have to overwrite the old files, if keeping the layers is important for you. You ought to be able tosave to a new directory.
That's what I'm trying to do; save to a different directory, save transparency, as a png file. The files I've been saving have been PNGs with a single non-background layer.
