使用像Image Baker这样的在线服务。

这很简单。在Android和iOS上上传图片和下载处理过的资产。

注:Image Baker是我的朋友和我自己创建的免费服务。

Just use https://romannurik.github.io/AndroidAssetStudio/index.html. It can make a set of icons from an image, later you can download a zip-file. Or download a Windows application at https://github.com/redwarp/9-Patch-Resizer/releases (doesn't need to install) and open an icon. Also you can use a plugin Android Drawable Importer, see answers above. Because it is abandoned, install forks. See Why does Android Drawable Importer ignore selection in AS 3.5 onwards or https://github.com/Vincent-Loi/android-drawable-importer-intellij-plugin. https://appicon.co/#image-sets.

一个bash脚本使用ImageMagick(转换)根据CommonsWare的答案:

增加了文件夹创建和参数检查多亏了Kishan Vaghela

#!/bin/sh
#---------------------------------------------------------------
# Given an xxhdpi image or an App Icon (launcher), this script
# creates different dpis resources and the necessary folders
# if they don't exist
#
# Place this script, as well as the source image, inside res
# folder and execute it passing the image filename as argument
#
# Example:
# ./drawables_dpis_creation.sh ic_launcher.png
# OR
# ./drawables_dpis_creation.sh my_cool_xxhdpi_image.png
#
# Copyright (c) 2016 Ricardo Romao.
# This free software comes with ABSOLUTELY NO WARRANTY and
# is distributed under GNU GPL v3 license. 
#---------------------------------------------------------------

if [ $# -eq 0 ]; then
    echo "No arguments supplied"
else if [ -f "$1" ]; then
    echo " Creating different dimensions (dips) of "$1" ..."
    mkdir -p drawable-xxxhdpi
    mkdir -p drawable-xxhdpi
    mkdir -p drawable-xhdpi
    mkdir -p drawable-hdpi
    mkdir -p drawable-mdpi

    if [ $1 = "ic_launcher.png" ]; then
        echo "  App icon detected"
        convert ic_launcher.png -resize 144x144 drawable-xxhdpi/ic_launcher.png
        convert ic_launcher.png -resize 96x96 drawable-xhdpi/ic_launcher.png
        convert ic_launcher.png -resize 72x72 drawable-hdpi/ic_launcher.png
        convert ic_launcher.png -resize 48x48 drawable-mdpi/ic_launcher.png
        rm -i ic_launcher.png
    else
        convert $1 -resize 75% drawable-xxhdpi/$1
        convert $1 -resize 50% drawable-xhdpi/$1
        convert $1 -resize 38% drawable-hdpi/$1
        convert $1 -resize 25% drawable-mdpi/$1
        mv $1 drawable-xxxhdpi/$1
    fi
echo " Done"
else
    echo "$1 not found."
fi
fi

最简单的方法是使用资源管理器

然后你可以选择每个密度

导入后，你可以看到这张图片的6个不同版本

不是100%自动，但我用Photoshop动作节省了很多时间。

例如，给定xhdpi资产，然后为hdpi和mdpi创建一个任务，其规模分别为66.66%和44.44%。然后运行文件夹xhdpi上所有图像的操作。

对于512x512的图像，所要做的就是计算缩放图像的百分比，以实现xxhpi、xhdpi、hdpi和mdpi。

使用Android Studio图像资产

至:

 Project>res --> right click

 new> image asset

然后设置:

-Icon type: Launcher Icons
-Asset type: Image
-Path: the/path/to/your/image
-Trim: No
-Padding: 0%
-Shape: None
-Effect: None

选择:Next > Finish。

Now you will have your icon in the correct resolutions.

编辑:我建议使用SVG图像来创建Vector Drawables，然后在画布中使用它们来调整它们的大小，或者简单地更改DP。

您可以从谷歌获取默认图标，也可以创建自己的图标

 Project>res --> right click
 new> vector asset

然后设置:

-Asset type: Local file (SVG, PSD)
-Path: the/path/to/your/image
-Size: check Override to keep your aspect ratio.
-Chek enable auto mirroring for RTL Layout.

选择:Next > Finish。

现在你将有你的图标，你将能够改变大小，颜色等。