Take our 100 x 100 pixel image again. Suppose it's set at 100 PPI (producing the same 1 x 1 printed image). With re-sampling off, when you adjust the PPI the dimensions adjust as well, this is how things worked in the example above. With re-sampling on, the dimensions won't change.
To dispose of charcoal and wood ash: Let the ash cool for 48 hours. You can speed up this process by pouring water over the hot charcoal and stirring it very carefully. When the ash has cooled completely, wrap it in aluminum foil and place it in an noncombustible outdoor trash bin.
Charcoal absorbs chemicals in the soil, water and air that can build up inside your terrarium over time and damage your plants. If you're skipping charcoal, make sure to use distilled water rather than tap water to avoid adding water treatment chemicals to your terrarium.