Kili Technology allows to work at pixel level to classify every single pixel of an image. The segmentation task is a continuous form : after selecting one category, start by a click, and, staying clicking, design the shape of the object. To complete the shape, just join the first point you drew. If necessary, you can substract a part of the form by clicking on the "x" icon in the toolbar.
It is also always possible to change the class of an annotation with a left click, selecting "Change class", and then select the new class of the object. If the task is multi-classification, this operation will allow you to select all the categories for this annotation : you can delete the previous class but also just add one or more others.
Segmentation can be nested (see nested classification)) with all classification tasks, to build refined image segmentation.