Comment 2 for bug 2027907

For "Nope, at the latest Pinta the image does NOT gets open", do you mean the latest flatpak build , or building Pinta from the 'master' branch?

Pinta 2.1.1 had a fix for bug 2003384 which affected drag and drop and sounds like the original issue you described with an error appearing but the file still opening successfully

The second error you described sounds maybe like a sandboxing / permissions issue where the file path can't be accessed. This might be something that's only fixed with GTK4 based on reading https://github.com/flatpak/xdg-desktop-portal/issues/99, but could be worked around by granting flatpak permissions to read the appropriate folders in the home directory?