Creating Android Asset Catalogs Manually
Android requires the following folders:
drawable
drawable-ldpi
drawable-hdpi
drawable-xhdpi
drawable-xxhdpi
drawable-xxxhdpi
Assets are copied directly into these folders using file names containing only lowercase letters, numbers (0-9), ".", and "_" (e.g., "my_header_image_14.png"). The file name used for the different versions of the image must be exactly the same in all folders. No sub-directories are allowed.
Other folders, such as
drawable-nodpi, may also be appropriate for your project. For more information, see
https://developer.android.com/guide/practices/screens_support.html, sections
Range of Screens Supported and
Using Configuration Qualifiers.