xss-lock i3lock with image

From my i3 config file:

bindsym $mod+u exec i3lock --image=/path/to/image

This locks the screen with a background image. Now I want to have a background image when suspending:

exec --no-startup-id xss-lock --transfer-sleep-lock -- i3lock --nofork --image=/path/to/image

This doesn’t work. When the computer wakes up, there is a blank screen.

How can I have i3lock display a background image when suspending, just like when just locking the screen?