in options - tile width pane, when all 3 checkboxes are turned off, tile width is limited to 1200 pixels.
i don't understand why it is limited to 1200?
i'm sorry i got confused. it was the tile height.
what i want to do is manually set the tile size to 800x1422 but it looks like the maximum manual height is limited to 1200.
Ok, I understood.
Currently manual set max resolution for a Tile is limited to 1600x1200.
That was made to avoid creation of too large screenlists.
I can increase that values for your own risk.