That’s work here 
If I understand right it works like a sandwich … upper covering lower … Is it right?
I will definitely chech them.
My img file now rises in size to 330MB and my device became quite sluggish.
The reason can be in size of file itself or because of drawing too much contours all the time.
I have three type of contours and would like to set different resolutions for them to not be displayed all the time, but only in appropriate resolution.
lines file
contour=elevation & contour_ext=elevation_minor
{ name ‘${ele|conv:m=>ft}’; }
[0x20 resolution 23]
contour=elevation & contour_ext=elevation_medium
{ name ‘${ele|conv:m=>ft}’; }
[0x21 resolution 21]
contour=elevation & contour_ext=elevation_major
{ name ‘${ele|conv:m=>ft}’; }
[0x22 resolution 17]
contour=elevation | contour_ext=elevation
{ name ‘${ele|conv:m=>ft}’; }
[0x21 resolution 20]
Any hint here? I don’t understand mainly 4th entry. 
regards
mira