Created attachment 155509 [details]
the applet with example image selected

SUMMARY
'Configure Desktop and Wallpaper' applet when applying a single image won't use files with a hashmark in the name;
taking out the hashmark fixes it

STEPS TO REPRODUCE
1. name an image with a hashmark part of the name, ie the character '#' (blanks irrelevant)
2. start 'Configure Desktop and Wallpaper'
2. select folder-view -> image
3. 'add image' , pick the image file with the # in the name
4 select the image just added, click apply

OBSERVED RESULT
wallpaper not changed

EXPECTED RESULT
image to be used as wallpaper

only tried on X11; seems like trying wayland would make no difference

OS: Kubuntu 22.10 x86_64 
Kernel: 5.19.0-29-generic 
Packages: 2892 (dpkg), 24 (snap) 
Resolution: 1920x1080, 1920x1080, 1920x1080 
DE: Plasma 5.25.5 
WM: KWin 
Theme: [Plasma], gnome-professional-40-dark [GTK2/3] 
GPU: Intel HD Graphics 630 
GPU: NVIDIA GeForce 210 +