The picture of your bathroom seems to have a line smoothing filter that the other pictures don’t have. It is a little blurred.
Hmmm, I'm not sure what you mean. all the images we done in Windows Paint. I don't think it is capable is it?
Newer versions of Windows Paint (since XP or Vista, IIRC) have all sorts of antialiasing features built in. Enough people missed using it to make clean pixel art that someone recreated the older version of paint to run in newer editions of Windows.
bedroom vs bathroom.
If you saved it as JPEG, it'll apply the smoothing. You might have saved it as a JPEG by accident.
For the image in questiom, you can try adding this to the base64_jpeg entry in the graphics {} section:
bathroom: base64_jpeg scaling_mode = "pixel_art" ....rest of line here..... ;
