I already saw that there is few stuff on it (e.g. KNIME Image Processing | KNIME) but my purpose would be to transform an image (.png or whatever), let’s say like this one :
Into a dataset (with columns and values). Is it possible and there is a node especially fit for this ?
Converting a table from an image into data is notoriously difficult.
See the conversations here for workflows and a general understanding of this topic. As well, for your problem you may also need to specify a language that KNIME may or may not have.