安卓规范中规定：应用apk文件中的IOCN必须是PNG格式。请您对apk内部的ICON格式进行检查

相应的格式修改必须用格式修改器进行修改，直接修改图片的后缀名是无法更改图片的格式的。

检查应用ICON是否为PNG格式，可以使用aapt工具，执行下面的命令：

aapt dump badging <apk包的路径>

检查输出内容中的所有声明的icon对应的图片是否是PNG格式

如下图红色字体部分：

package: name='com.xiaomi.market' versionCode='111' versionName='0.9.1'
sdkVersion:'9'
targetSdkVersion:'15'
uses-permission:'android.permission.INTERNET'
uses-permission:'android.permission.ACCESS_NETWORK_STATE'
uses-permission:'android.permission.WAKE_LOCK'
uses-permission:'android.permission.ACCESS_DOWNLOAD_MANAGER'
uses-permission:'android.permission.ACCESS_DOWNLOAD_MANAGER_ADVANCED'
uses-permission:'android.permission.ACCESS_ALL_DOWNLOADS'
uses-permission:'android.permission.SEND_DOWNLOAD_COMPLETED_INTENTS'
uses-permission:'android.permission.INSTALL_PACKAGES'
uses-permission:'android.permission.DELETE_PACKAGES'
uses-permission:'android.permission.RECEIVE_BOOT_COMPLETED'
uses-permission:'android.permission.GET_ACCOUNTS'
uses-permission:'android.permission.AUTHENTICATE_ACCOUNTS'
uses-permission:'android.permission.MANAGE_ACCOUNTS'
uses-permission:'android.permission.USE_CREDENTIALS'
uses-permission:'android.permission.READ_PHONE_STATE'
uses-permission:'android.permission.ACCESS_WIFI_STATE'
application-label:'应用超市'
application-icon-160:'res/drawable-hdpi/icon.png'
application-icon-240:'res/drawable-hdpi/icon.png'
application: label='应用超市' icon='res/drawable-hdpi/icon.png'
launchable-activity: name='com.xiaomi.market.ui.MainTabActivity'  label='' icon=''
uses-feature:'android.hardware.wifi'
uses-implied-feature:'android.hardware.wifi','requested android.permission.ACCESS_WIFI_STATE, android.permission.CHANGE_WIFI_STATE, or android.permission.CHANGE_WIFI_MULTICAST_STATE permission'
uses-feature:'android.hardware.touchscreen'
uses-implied-feature:'android.hardware.touchscreen','assumed you require a touch screen unless explicitly made optional'
main
other-activities
search
other-receivers
other-services
supports-screens: 'small' 'normal' 'large' 'xlarge'
supports-any-density: 'true'
locales: '--_--'
densities: '160' '240'