ᐅ Quick question: Is this normal algae growth or green mold?

Hello everyone,

Briefly, this is 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 growth due to a leaking roof, or could it already be green mold?

Any advice on removal, regardless of whether it’s algae or mold? Is it necessary to knock off the plaster and replaster?

Thanks for your help.

Is that on the inside or outside?

To me, it looks like water has run down there and caused the green discoloration. I don’t think it’s mold. I would wash it off and possibly repaint.