Quick question: Is this normal algae growth? Or green mold?

Hello everyone,

very briefly, it's about a shed where the roof had collapsed. The picture shows some green spots on the wall. From a distance, do you think this is more likely algae due to a leaking roof, or is it already or could it already be green mold?

Any tips for removal, no matter what it is, algae or mold? Is it necessary to knock off the plaster and replaster?

Thanks for your help.

Is that inside or outside?

To me it looks like water has run down there and caused it to turn green. I don't think it's mold. I would wash it off. And possibly repaint.