Painting differs 1 cm

[Stina]

What do I do now? The painting is 32.3 cm on the right side and 33.2 cm on the left side.

Canvas glued to wood.

I’ve been thinking of adding some kind of spacer. But I really don’t know.

[Justintime]

A bevelled fillet inside the frame rebate would be best, but I don't dislike your gold spacer. You have the right idea, you will just have to see what you can find from your local suppliers. If you have access to a bandsaw you could stack two gold mouldings but cut the inside one down, reducing it in depth to remove the rebate.

[NTG999]

I would something like this from Wessex Pictures, different widths available

[Justintime]

Not sure Steve delivers to Sweden

[prospero]

I would make the frame to the shortest dimension then lay it face-down in the frame and draw around the part where it
overlaps with a pencil. Then nibble out the excess with a Dremel+sanding drum. A dusty procedure but I've done it many times.