How do I fill a texture with another texture? I created a small tileable texture in blender. Now I need to fill a larger texture with the small texture. 



I need to use the above texture on a large plane so it tiles.(like tiles) But when I use the fill brush it only fills a color, not the texture. How do I solve this?

Sorry if the question is not clear. Thanks in advance.
Easiest way how to blend textures is mix them together using "Colors" -> "MixRGB"  node in node editor:


Second option is use external image editor Like GIMP, Krita, Photoshop etc.
For fast and easy workflow you can set path to your image editor in 

"File: -> "User Preferences" -> "File" -> "Image editor"

Now you can send your texture to your external image editor from Blender UV/Image editor by 

"Image" -> "Edit externaly". 

If you finish editing in external Image editor, just overwrite original image and In Blender Image Editor use 

"ALT+R" for reload your edited image.