By default the texture scale is default to 1. However if you want to have a custom texture scale, you can edit YOUR_WORKSAPCE/setting/texture_options.json, or create one if not exist. Here's the sample structure of the config file

{
	"YOUR_2X_ASSET": {"scale":2}
}

Starling Builder is trying to match the url for every texture with every key. If there's a match the texture scale value will set to the value of the config. The key can be a regular expression.

You can also specify a default scale factor other than 1 like this

{
	"default_option": {"scale":2}
}

Besides scale, you can also set other TextureOptions properties (mipMapping, format and repeat) in the value.

You can use the ignore_assets fields to exclude certain assets to load into the editor. The following example will ignore all the files end with “.jpg” and “.JPG”.

{
	"ignore_assets": [".jpg$", ".JPG$"]
}