Problem while saving some files

Hi,
I was trying to mod the bullet account textures, but, when I tried to save the textures, it didn't work and said me the image height and lenght must be a multiple of 4... And I can't change the size or it will get me an error... Any idea?
Thanks

certain files cant be converted correctly by the converter. I forget exactly what it is but thers just some files you cant edit without a more powerful converter. :/