img {
  display: block;
  max-width:100%;
}

concatCss(targetFile, options)

targetFile: The relative path of the generated file containing the concatenated css
options: (since 2.1.0)
inlineImports: (default true) Inline any local import statement found
rebaseUrls: (default true) Adjust any relative URL to the location of the target file.
includePaths: (default []) Include additional paths when inlining imports
commonBase: (default to the base property of the first file) Common base path from wich resolving files and urls