Hello everyone.
I am looking for advice regarding a functionality I am currently working on.
As part of the app I am developing, I have to give users a way to draw on pictures they have previously taken and save the result in SharePoint. Unless I missed something, it's currently impossible to do so directly with canvas. Therefore, I tried doing the next best thing.
1- As these photos have to be stocked with and without alterations, I first send them to my SharePoint.
2- I set up a gallery that allows to select the SharePoint pictures and to have them on the app screen, under a drawing control with a transparent background.
3- I then added to this the screenshot PCF (https://pcf.gallery/screenshot-pcf/) in the hope of completing this function.
Right after I started boasting about my novel solution to my coworkers, I realized that the screenshot PCF does not capture images, and I don't really understand why.
Here is a screenshot of my setup with my gallery, drawing, image and screenshot controls

And here is another screen with the screenshot taken by my the previous control and a label with the content of the image file I believe to be in a base64 string format. As you can see on the picture, the big image and the miniatures of my gallery do not appear in the screenshot taken in my app.

Finally, here is my question :
Can anyone tell me how to capture images using the screenshot PCF or, even better, has an alternative way to draw on an image in a Canvas app and save the result in SharePoint ?
A good day to all of you,
Seb