Hi VasiliyFamiliya!

All my GFX use the RGB value for Magenta as the background colour.

R - 255
G - 0
B - 255

Your GFX can have more than 1 palette but initially try to use 15 colours + magenta. Just to make sure you can get the magenta to be ignored.

I believe the magenta is hard coded so that when GFX are compiled it gets ignored. If I remember correctly HPMAN also supports transparent .pngs so the Transparency will also be ignored after the GFX are compiled.

Tip: Open HPMAN's Blue Mary Sprite and sample his background colour.

The official documentation has this info.... Probably in the "Framer" section.