This is result for 1920x1080 monitor:
https://i.imgur.com/pvEV7Yd.jpg

This is the ahk code:
hotkey, home, functionB

functionA:
gui destroy
{
gui, destroy
hotkey, home, functionB
}
return

functionB:
{
xcoordinateini:=1540
ycoordinateini:=663
Gui, Color, FFFFFF
Gui, +LastFound +AlwaysOnTop +ToolWindow -Caption
WinSet, TransColor, FFFFFF
Gui, Add, Picture,x%xcoordinateini% y%ycoordinateini% +BackgroundTrans, %A_WorkingDir%/chat.bmp
Gui Show, x0 y0 w1920 h1080 NoActivate
hotkey, home, functionA
}
return




;chat.bmp is 337x227 black bitmap