but since I found out it ain't supported by RPG Maker
Nobody told you that Graphics Gale is not supported by RPG Maker. What you have been told is that the
.gal file extension is not supported and that Graphics Gale is not
directly supported, but Graphics Gale
does allow you to export your files in PNG, and PNG files
are supported by RPG Maker.
The only thing that matters is how you format your sprite sheet, as Theo explained above. But until you provide further details I am afraid we cannot help you. Nobody can read your mind, if you do not provide enough information it is impossible to help you. When somebody helping you asks for more information, it usually means that the person itself needs that kind of information in order to help you.
In relation to this particular topic, what you are trying to achieve is quite simple, but you are keeping the most crucial information for yourself, and this nobody is able to help you.