PEAK XOOPS - How to create icons for D3 modules

If you develop D3 module, set the base png with "indexed colors".
And you should not its color depth as 32,64,128 or 256.

I recommend you to save the png as 63 indexed colors.

This is bulletin2's module_icon.png with 63 indexed colors.
(You can understand what I mean, just by replacing module_icon.png under xoops_trust_path/modules/bulletin/ )