The previous article "Multiple image compression solutions under CentOS" shared three different compression solutions, and in this article, an additional open-source project called mozjpeg from Mozilla will be added, which can effectively compress JPEG images.

Install Mozilla JPEG

Source code download link: https://github.com/mozilla/mozjpeg/releases

# Install nasm environment
yum -y install build-essential nasm
# Download source code
wget https://github.com/mozilla/mozjpeg/archive/v3.3.1.tar.gz
# Unzip
tar -zxvf v3.3.1.tar.gz
# Enter the directory
cd mozjpeg-3.3.1
autoreconf -fiv
# Compile and install
./configure
make && make install

After successful installation, the binary files are located in the /opt/mozjpeg/bin directory and can be directly copied to the /usr/bin directory for direct use. The cjpeg is mainly used for image compression. Enter the following command to copy:

[root@aliyun-sgp ~]# ll /opt/mozjpeg/bin
total 256
-rwxr-xr-x 1 root root 56816 Nov 16 13:42 cjpeg
-rwxr-xr-x 1 root root 45864 Nov 16 13:42 djpeg
-rwxr-xr-x 1 root root 53504 Nov 16 13:42 jpegtran
-rwxr-xr-x 1 root root 13624 Nov 16 13:42 rdjpgcom
-rwxr-xr-x 1 root root 64592 Nov 16 13:42 tjbench
-rwxr-xr-x 1 root root 13624 Nov 16 13:42 wrjpgcom
[root@aliyun-sgp ~]# cp /opt/mozjpeg/bin/cjpeg /usr/bin/

Compress images

Mozilla JPEG only supports compressing JPEG images. The compression command is as follows:

cjpeg -quality 80 xxx.jpg > xxx_1.jpg
# or
cjpeg -outfile xxx_1.jpg -quality 80 xxx.jpg

The above command means compressing xxx.jpg and save the compressed file as xxx_1.jpg with a compression quality of 80.

• -quality: Specifies the compression quality (0-100). If not specified, the default is 75. The larger the value, the faster the efficiency, but the worse the compression quality. It is recommended to keep the default value.
• -outfile: Save the compressed image as a new file, or use the redirection symbol >.

Other instructions

• mozjpeg project address: https://github.com/mozilla/mozjpeg
• Some content of this article references: Introduction to Image Compression MozJPEG CentOS 7 Compilation and Installation