Just came across this and love it. I had been using a cross stitch pattern site up to this point. One thing it has that I would love to see implemented here is an import option of color studs to use. It used a csv file import as an example of the file, here is the color palette I used on my last project.
#1b2a34,01
#ffffff,02
#8c8c8c,03
#969696,04
#3e3c39,05
#aa7f2e,06
#00852b,07
#a5ca18,08
#720012,09
#b40000,10
#68c3e2,11
#1e5aa8,12
Anyways, just an idea as the current method to remove colors from the list takes awhile. Another option may be to allow multiple changes to be made, then clicking a refresh/redraw image button, instead of waiting for every change being made before making the next adjustment.