Go to Options> Element Attributes> Materials and select you mosaic tile material from the list. There is an option to show the settings for Internal Engine or Lightworks methods. If you go to Internal Engine first, check the size of the texture image in the bottom panel. Then go to the Lightworks method, and check the size in Texture Space setting (see below). S Size and T Size should be the same as Internal Engine method. There is also a scale setting within the Colour settings for the image.
An easy way to make Lightworks materials the same as Internal Engine materials is to simply hit the "Match with Internal Engine" button, but be aware that this changes all settings, including possibly some you don't want to change, which is why I suggest just checking the image size first. It's usually a good place to start, though.
