graphic symbols, size control

I have still a problem for control of the size in dorico of a glyphe imported from an image graphic file ( png of jpg)
the graphic appears normally in the preview, but in not viewable when imported in the score, and the scale functions seems inoperative…

It it somewhere a small tutorial for such symbol creation?
( the problem seems the same either for playing technique creation from the same graphic).

What should be the initial size of the imported graphic?

Thanks for any help…

screen copy Playing tech (57.2 KB)

It would be easier to diagnose this problem if you can provide the project file or at least the graphic itself, JF. For a simple graphic like that, I suggest you draw it as an SVG using a vector application like Inkscapde, Affinity Designer, or Illustrator. Setting the scale for both X and Y to something like 10% is a good start; that should help you to get a handle on its size in the preview.

Thanks for your interest and quick reply…

I created the graphic using the forms under office Windows then exporting as image
File attached…
symbole en boucle.png

The first thing you should do is trim the image so that there is no white space around the borders of the graphic. And I think you will find it easy enough to produce a proper scalable version of this image by tracing it into an SVG in an illustration program.