Regarding IPB's smilies copyright

[Snake]

There has been many issues with the current smilies that I'm using on my vBulletin board and so I have got a few questions regarding the use of IPB smilies on vBulletin boards. The smilies which I'm using can be found right here and as you can see for yourself, they are quite looking like the yellow ones which was made by you guys - the IPS team. Here are a few examples:



Anyway, that site had just to change it's color to blue and fix the background to transparent so it should work fine on all dark skins. That is all, nothing more to it. I have received a few complains from their staff that it is known as "plagiarism" because of their smilies that are being used on my forums. I thought there was no need for their permission because the smilies were actually and originally made by IPB and that they aren't even running on IPB. Also I thought those smilies can be freely used and distributed to all. And on top of that, didn't they had to contact IPS and have the permission first whether they are allowed to modify the smilies to their liking or not?

Any answers from the IPS team or others is greatly appreciated!