Having trouble importing maps and having the grid be able to lie up across the map

I've been trying things and searchign online for a while now trying to resolve some kind of scaling issue when I import maps into FGU. I've been working on importing Abomination Vaults 3 (I'll buy the product when it's out, but it gives me a project to work with) as a means of getting more comfortable with building things from scratch inside FGU. THe problem is that no matter what I try in PS the maps never seem to be properly scaled to use the FGU grid. There seems to be a scaling error that's cummulative from wherever I set the inital grid up. So clearly I'm not prepping the map image file properly in PS and I don't know what step(s) I'm missing so I'm hoping someone can get me pointed in the right direction?

I've attached an image showing the issue. THe red circled area is where I setup the grid, the blue area is just further away to highlight the issue.
Attachment 47075

Try a couple of things:
1) Line up the grid in the middle of the image - this will result in any drift being less noticeable.
2) Use the smaller buttons in the "joystick" control to nudge the grid size in 0.1 increments to try to make it line up better.
3) If the map has a grid on it - get it as close as you can using the two above steps, then make the grid invisible. The grid will still be there on the base map, but you won't see it - and it should be close enough to allow movement and distance measurement, but you don't see the obvious drift.

In the end though, if the original image has drift in it then you'll either have to live with it or try to fix it yourself by doing non-linear scaling in the original image (not easy). You could also see if this helps: https://www.fantasygrounds.com/forum...gn-map-to-grid

Thanks for the tips, I'll give that a shot!

You may wish to have a look at this utility https://www.fantasygrounds.com/forum...gn-map-to-grid

See the links at the bottom of the first post by myself and Trenloe for how to use it for your circumstances.

Edit: Oh, Trenloe already linked it. I didn't read all of his post first :)

The Map Align ultility has saved my bacon, thanks Trenloe!