Permanent xrandr commands in ~/.xprofile

I'm trying to make these xrandr commands permanent in ~/.xprofile but for some reason it's not taking effect. Am I doing something wrong? Thanks!

xrandr --newmode "1600x1200_75.00" 204.75 1600 1720 1888 2176 1200 1203 1207 1255 -hsync +vsync
xrandr --addmode VGA-0 1600x1200_75.00
xrandr --output VGA-0 --mode 1600x1200_75.00

Edit: So apparently I'm using SLiM which doesn't read .xprofile.

Edit 2: I had to add this to /.xinitrc and it's working now.

[ -f /etc/xprofile ] && . /etc/xprofile
[ -f ~/.xprofile ] && . ~/.xprofile

As a side note, I just noticed SLiM is outdated and I should be using LXDM.