Originally Posted by
LordEntrails
Make sure you're not getting confused with 'dpi' (dots per inch, which only has to do when you print something, and nothing to do with how something is displayed on a computer screen) and how grids are rendered in FG.
As mentioned, without that extension, 5E uses a grid that represents 5 ft. That distance is only used in displaying sizes for pointers (unless you are using one of the few extensions that use the range for other things).
When it comes to token scaling, if you turn on the GM option for automatic scaling, the tokens will automatically scale to 80% (or whatever you set the option value to) to the grid size (one grid for medium, 4 for large, etc). You can also manually scale tokens, or if all tokens are the same size in pixels, you can set the scale of one token, then use the 'Lock Token Scale' function.
I worry that you are trying to fight the system to get what you want, and not understanding or know of some of the built in functions in FG.
In almost every case, it should not matter what the image size/resolution/pixels per square is of the map image. As long as it's an evenly divisible number, you just place the grid in FG (42 pixels, or 50, or 72, or 113...) and then tokens get scale automatically etc. Note, you might end up using tokens from different sources, and these might have different pixel sizes (i.e. some might be 100 pixels, other 150 or 200); and the best way to handle that is to use FG's automatic scaling.