What is a collector card?
How do you gain one?
What is the reason of having it?

It's a collectors item, and you can customize them by uploading a picture to it and changing it's name.

You can just buy them from other people that have one for sale, only way how I think.

The reason why you should have one, it's cool to have an item which has your name and picture in it.

But how do you attain one to upload a pic at the first place?

Well, like this guy here has some for sale: http://forum.toribash.com/showthread.php?t=563057
I guess that's the reason you made this thread but besides that.

People can just buy one of the cards off of him for tc, like any other item. You could get the cards in some different way before, but nowadays, only way to get them is like that.

If you've bought one, you can just click on the icon of the item and upload a new picture to it. All of the pictures on the cards in the thread I linked are custom requested pictures, you can let someone make a picture like that specially for you in the art board too.

So cards are re-editable?
Or once uploaded they are permanent?

Pretty sure they are re-editable.

The card is like any other texture in the game. Upload and reapply any time you want. It's just an item that sits in your Deact. No reason to have one besides selling, keeping or giving to a friend

Thanks 7th, I never owned one so I wasn't 100% sure about that one.

Looks like everything's said in here, closing. Feel free to pm me or reopen this if you have any more questions about this.