The Height command returns the height information of the image img.

$\mathrm{with}\left(\mathrm{ImageTools}\right)\:$

$\mathrm{img}≔\mathrm{Create}\left(10..59\,1..200\right)\:$

$\mathrm{Height}\left(\mathrm{img}\right)$

$50$

$\mathrm{map2}\left(\mathrm{Height}\,\mathrm{img}\,\left[\mathrm{size}\,\mathrm{lower}\,\mathrm{upper}\,\mathrm{range}\right]\right)$

$\left[50\,10\,59\,10..59\right]$