1、先到官网上下载源码http://www.ijg.org/files/jpegsr9.zip 最新的是jpegsr9

2、然后加压，生成jpeg-9,进入并创建jni目录，将里面的内容都拷贝到jni里面

3、生成配置文件，在jni目录下面创建config.sh文件，然后在里面添加：

NDK=/opt/android-ndk-r8d
PLATFORM=$NDK/platforms/android-8/arch-arm/
PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86
CC=$PREBUILT/bin/arm-linux-androideabi-gcc
./configure --prefix=/home/jpeg-9/jni/dist --host=arm CC="$CC --sysroot=$PLATFORM"

4、然后改变config.sh的权限，并执行,得到配置文件：

chmod 775 config.sh
sh config.sh

5、生成Android.mk文件，内容如下：

LOCAL_PATH := $(my-dir)

include $(CLEAR_VARS)
# From autoconf-generated Makefile
LOCAL_MODULE := libjpeg
LOCAL_ARM_MODE=arm
LOCAL_SRC_FILES := \
jaricom.c \
jcapimin.c \
jcapistd.c \
jcarith.c \
jccoefct.c \
jccolor.c \
jcdctmgr.c \
jchuff.c \
jcinit.c \
jcmainct.c \
jcmarker.c \
jcmaster.c \
jcomapi.c \
jcparam.c \
jcprepct.c \
jcsample.c \
jctrans.c \
jdapimin.c \
jdapistd.c \
jdarith.c \
jdatadst.c \
jdatasrc.c \
jdcoefct.c \
jdcolor.c \
jddctmgr.c \
jdhuff.c \
jdinput.c \
jdmainct.c \
jdmarker.c \
jdmaster.c \
jdmerge.c \
jdpostct.c \
jdsample.c \
jdtrans.c \
jerror.c \
jfdctflt.c \
jfdctfst.c \
jfdctint.c \
jidctflt.c \
jidctfst.c \
jidctint.c \
jquant1.c \
jquant2.c \
jutils.c \
jmemmgr.c \
jmemnobs.c
LOCAL_C_INCLUDES := $(LOCAL_PATH)
LOCAL_CFLAGS :=-O3 -fstrict-aliasing -fprefetch-loop-arrays -DANDROID \
-DANDROID_TILE_BASED_DECODE -DENABLE_ANDROID_NULL_CONVERT

include $(BUILD_SHARED_LIBRARY)