Off by two issue and only tiny images are allowed to be set with _NET_WM_ICON
For _NET_WM_ICON first two cardinal items are the dimensions of the icon. Because MAX_ELEMENTS is set to 64, this means the maximum icon size is 8x7 or 7x7 pixels. I set MAX_ELEMENTS to 2048 and was able to set a 32x32 pixel icon.
What do you think about bumping MAX_ELEMENTS to a larger size to allow icons to be manually set?
When the default format is set for _NET_WM_ICON ('o') I get bad format character: o
strangely enough, so I've been using -format _NET_WM_ICON 32c
which works