JPEG format, or JPG, is a widely-used raster graphics format in print and on-line. It is also the most common format for still digital camera output. JPEG stands for Joint Photographic Experts Group, Today, the JPEG format is an open standard format that is jointly maintained by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC),
Lossy or Lossless Compression
The terms “lossy” and “lossless” refer to what happens to an image’s integrity during the compression process. When an image stays exactly the same when compressed, it’s called a “loss”less compression. The image is exactly the same after being resized. In lossy compression, the colors of pixels are changed to fit a smaller size. This is “loss”y compression. The image will look good because of the intelligence applied to color it properly when scaled. However, it will never be exactly the same again.
Creating JPEG – Convert PDF to JPEG
Most of today’s paint and graphics programs save files in JPEG (also known as the JPG format). Screen capture utilities and Web design tools also do. If you need to convert PDF to JPEG, use pdf2image and pdf2picture. JPEGs can also be generated programmatically using the PDF Conversion Server via command-line or the PDF Conversion SDK API.
JPEG compresses both full-color and grayscale images. Its target is digital still photographs and realistic images. For line art, lettering, cartoons and other graphics with few colors and sharp lines, PNG is best suited.
JPEG is very good at compressing rich color images without any perceptible change in the file. This is lossy compression. Even though colors drop to achieve compression, it’s balanced so that it fools the eye. If you decompress the image, it doesn’t regain the same quality as the original. GIF and PNG are lossless formats. Compressing them doesn’t change the image.
JPEG Format – Example
The JPEG format serves two primary purposes: it makes image files smaller and it stores 24-bit per pixel color data (full color) which is better in many cases that 8-bit per pixel data. Making image files smaller is essential for storing and transmitting files. Being able to compress a 2MB full-color file down to, for example, 100KB makes a big difference in disk space and transmission time. JPEG can quickly provide 20:1 compression of full-color data. With GIF images, the size ratio is usually more like 4:1.
Support Notes
- Visual Integrity solutions output to 24-bit color with JPEG encoding by default
- Output to the JPG format in any dpi resolution or pixel size (preserving aspect ratio)
- Source files for conversion to the JPEG format may include vector graphics, raster images, and font text strings
- Advanced anti-aliasing applied during the conversion process
- pdf2image and pdf2picture are desktop programs that convert PDF and EPS files to the JPEG format (JPG Format)
- Convert PDF to JPEG programmatically using the PDF Conversion Server via command-line or the PDF Conversion SDK API.
JPEG Format Alternatives to Watch
JPEG first appeared in 1986. The joint standard has evolved over the years to support the innovations in storage and computing capabilities. Today, options for high-end imaging are proliferating. All of the new formats have significantly improved compression and image quality.
- JPEG 2000 is from the originators of JPEG – Joint Photographic Experts Group and is wavelet-based. It was designed as the successor to jPEG. What makes it stand out, is that it can be either lossy or lossless. It promises high quality and low latency.
- JPEG XR is a compressed image format used primarily for HD Photo files. It supports monochrome, CMYK and bit-depths of 16 or greater.
- WebP is an image format developed by Google. It supports both lossy and lossless compression in Chrome and Opera. It’s derived from the VP8 video format.
- HEIC is a format supported by Apple as a replacement for the JPEG format in iOS.