It's just educated guess -> but gallery seems pan-saves files (either game reads all saves at the start - or even has separate gallery state) - which means save editing in browser will not change anything with gallery in steam - you should probably cleanse whole save files from steam to achieve that.
Edit:
Yeah game reads cg and busts from this:
Options.systemOptions.cgs
Options.systemOptions.busts
You can inspect and change them in browser but that will not be transferred via save/load to file. Unless there is a method to move all data including options to steam. But that I'm not aware off as I don't own steam version.
Edit2: and ofc this is assuming game is not ALSO reading all present save files to actively update this variables on start of the game or on load of save.