[RM2K] Problem with smooth colors on importing the edited images back

Hi guys. I'm currently working on Seraphic Blue translation, and I've been struggling a lot with importing the edited background menu images back. The problem is that I use the same background for every image, and on some of them the colors stay smooth in the game:

...and on some the smoothness becomes completely broken:

I did read this article, but before going deeper I just want to be sure that there isn't a more simple solution, because again, some of the images I edited didn't get all messed up for some reason.

Honestly, it's the first game where I've got a problem like this, so I'm not that experienced in using IfranView for fixing images (or better say, I don't know how to use it at all). I presume the problem is in the writings, because when I tried to import just a blank background, it worked perfectly fine.

Anyways, if anybody's willing to help me, here's the link with the folder containing the examples of edited images and the original ones. I don't want you to fix it for me ofc, I just want to know what makes the problem:

Thanks beforehand.

[RM2K]How to make a stage music continue playing during battle encounters?

Hi, guys. Is there any way to prevent battle encounters from interrupting the stage theme? I tried to put the "Change System BGM" before the encounter and set it to "OFF", but all it does is just mute all the music. Maybe there's some other way exists? I know it was possible in Seraphic Blue, but it has its own customized (and very complicated) system, that I'm not sure I would understand.

Thanks beforehand.

Hi, guys! Seraphic Blue, anybody?

Hello, everyone! I only hope it won't count as spam, but I have a big crush on that game and currently I'm making a fandom page about it. I know, this game doesn't have much fans around the web, but if anybody would like to participate or just to pay a visit, you're welcome! (beware! Bad engrish ahead!)

There is not much content for now, but we're slowly working on it.

About other games, right now I'm playing Alter AILA Genesis and Hellsinker, also liked:
Hello Charlotte
Pocket Mirror
Space Funeral
Lisa (didn't really like the third game though)
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