So SonMapEd keeps doing this weird thing where if I save a sprite to my computer, edit it, and then put it back on SonMapEd, it will change all transparent parts around the sprite to the color of Sonic's nose and get rid of the color blue and make it transparent. How would I fix this? It prevents me from editing a lot of stuff. And the weirdest thing about it is that it only does this with certain sprites.
It's basically trying to match up the exact colors of the sprite that your trying to add with the ones already in game Utilizing the first palette line so that is to be expected when using SonmapEd. If I'm not mistaken, I believe you have to go to [Settings>Image Importing] and turn on/off the Assume Corner is Background option to fix the transparency problem. as for the other problem with the Palettes, the same thing. go to [Settings>Image Importing] except this time you would choose Direct/Nearest match to current palette, or if that option is already set, try setting it to Normalize match to current palette Instead.
