Use Of Own Filters?

Hi i have made some of my own filters and customized a few which i downloaded alot, i was just wondering, is there any restrictions on giving away free textures made by exporting the results to .bmp ect? like do we have to credit the company and that type of thing are are they royalty free with no restrictions.

Edit - reading through what was said in a previous post about using others filters in you work i found a bit which basically says if you made it then you can do whatever you want with it so i guess that applies for the .bmp's also and no credits are needed?