chds = 0,1800
https://image-charts.com/chart?chd=a%3A2060%2C971%2C849&chds=0,1800&chs=700x100&cht=bvg
chds = 0,2000
https://image-charts.com/chart?chd=a%3A2060%2C971%2C849&chds=0,2000&chs=700x100&cht=bvg
So chds = 0,1800 has a lower bar than chds = 0,2000 when I expect the opposite. With chds = 0,1800 I expect the bar to take up the whole image since 2060 is more than 1800.
Docs: https://documentation.image-charts.com/reference/chart-axis/


Image-Charts founder here :)
As per our documentation, chds as you want to use it works with
chd=t:(like in Google Image Charts).chdsis not necessary withchd=a:.With
chd=t:chdswork as expected:chds=0,1800&chd=t:
chds=0,2000&chd=t: