For best performance and quality, we usually recommend that all source textures be converted to Air texture files for rendering with Air. This conversion can be accomplished using either the the mktex command line tool or the mktexui user interface tool. The resulting texture file contains filtered versions of the texture at different resolutions, each version stored as a set of tiles. This arrangement allows Air to efficiently load sections of an image on demand at an appropriate resolution to produce high-quality anti-aliased texture results.
During the conversion to an Air texture file, the source image can also be converted from a nonlinear color space such as sRGB into the linear color space that is appropriate for Air’s shading computations.
Now, although conversion to Air texture files is the recommended procedure, sometimes that is not possible or desirable. In particular, Massive will not automatically convert source images to Air texture files when exporting a scene with default agent materials for rendering with Air. The latest versions of Air have a couple new options to improve the workflow in this case.
Air 13 has a new option to specify the color space for source images used as textures that have not been converted to Air texture files. This option can be used to automatically convert textures in sRGB color space to linear color space:
ColorSpace "rawtexture" "sRGB"
Air 13.02 introduces a new option to automatically create an internal tiled, filtered texture from any unconverted source texture image:
Option "texture" "automipmap" 
Either or both of these options can be placed in a small text file, and that file can be specified as the options rib file in the render pass settings dialog in Massive. Alternatively, the options rib can be passed on the command line prior to the main scene file:
air opts.rib myscene.rib