opening an image in /tmp with Pinta

I have Pinta 2.1.1 running in Flatpak (v1.14.5). When I run Pinta from the command line passing an image located in /tmp as an argument, it complains about the file not existing:

$ /var/lib/flatpak/exports/bin/com.github.PintaProject.Pinta  /tmp/img.jpg 

Pinta: GLib.GException: Error when getting information for file “/tmp/img.jpg”: No such file or directory

I am guessing this is due to [/tmp being blacklisted by default](https://docs.flatpak.org/en/latest/sandbox-permissions.html) , and Pinta [not configured](https://github.com/flathub/com.github.PintaProject.Pinta/blob/7d1e540906c8f52af7e9060aded28cf755f1456b/com.github.PintaProject.Pinta.yaml#L12-L33) to enable access to it. However, once the application is running, said image can be opened via 'Open file' (Ctrl+o) dialog. Is this expected?