Hi olivierr,
Welcome to Affinity Forums :)
Yes, here's how (after you have rotated the picture):
- create a new Fill layer going to menu Layer ▸ New Fill Layer (to fill the transparent areas left by the rotation operation)
- move the Fill layer to the bottom of the layers stack in the Layers panel, right click on it and select Rasterise... (so you can merge it in the next step)
- select both the image and the Fill layer (now a Pixel layer after you have rasterised it)) in the Layers panel and merge them going to menu Layer ▸ Merge Selected.
- now select the Inpainting Brush Tool and paint over the solid colour areas of the old Fill layer. It should fill them with data from the image.
