ImageOptim API features in detail
Advanced JPEG compression
ImageOptim API uses a custom JPEG encoder with features to improve compression as well as increase quality of compressed photos:
- Trellis quantization, optimized Huffman tables, scan split optimization — advanced techniques for maximum file size reduction.
- Progressive rendering — only 15% of image data is needed to start displaying it on screen.
- Overshoot deringing — makes text and lines on white background appear sharper.
- Quantization tables optimized for high-DPI screens — avoids bloating files with details that are invisible to the naked eye.
- Gamma-correct chroma subsampling — highly-saturated lines and edges are sharper and higher quality.
- Color fringing reduction — patterns on colorful backgrounds appear sharper.
Some of these features were developed specifically for the ImageOptim API and are not available anywhere else.
Color profile support
- Correctly supports reading images in CMYK, Adobe 1998 and other color profiles.
- Non-standard and filesize-heavy embedded color profiles are converted to most efficient, minimal alternative profiles.
Lossy PNG compression
Uses the latest version of libimagequant to reduce file sizes of true-color PNG files by 75%.
Resizing for thumbnails and responsive images
ImageOptim API has a high-quality implementation of the usual resizing and cropping options:
- Processing is done in linear-light 48-bit color to ensure highest quality.
- Anti-aliasing filters are optimized for JPEG compression to improve file sizes.
- Aspect ratio is always preserved.
- Automatic cropping based on saliency detection.
- Easy URL syntax for HTML5
srcsetfor high-DPI displays. - Multiple quality presets tuned for mobile networks, high-DPI displays, and pro photography.
Flexible HTTP API
If your website already has a back-end for processing images, you can keep it, and enhance it with ImageOptim's API. On the other hand, if you don't have an image processing back-end, you don't need to build one.
- On-the-fly resizing and conversion — optimized images can be generated on demand by proxying them through ImageOptim's CDN. No programming necessary.
- Your own hosting and storage — it's possible to use ImageOptim API as a tool for processing images ahead of time (e.g. when they're uploaded, or to optimize an existing collection of images), so that you keep full control over your images.
You don't need to install or maintain any image processing software on your servers.
Full compatibility
- Generated images are compatible with all major browsers and operating systems: Internet Explorer 7 and newer, Edge, Chrome, Firefox, Safari, Opera, Opera Mini (all browsers in their desktop and mobile versions) as well as native image viewers on iOS, Android, Windows and macOS.
- The ImageOptim API can be used from PHP (including Wordpress), NodeJS, as well as any other server-side language able to make HTTPS requests (Python, C#, Java). The on-demand API can be used by any website on the public Internet.
Privacy
Private data (e.g. GPS location in photos) is stripped from images compressed by the ImageOptim API.