MultiRes - Multi-resolution image viewer
MultiRes is an image format that makes images look good on all screen resolutions, from mobile displays to Retina displays.
Test it now! Zoom in to the photo on the left. You can use Ctrl/Cmd-+ to zoom in. Note how the GitHub banner gets pixelated but the photo stays sharp.
You can see more examples on the sample images page.
When an image is zoomed out, MultiRes loads a smaller version of the image. When you zoom in to the image, MultiRes loads a larger version of the image.
How MultiRes works
MultiRes keeps each screen pixel filled with at least one image pixel, up to the maximum resolution of the image.
A MultiRes image directory contains several versions of the same image at different resolutions.
The MultiRes viewer loads the version of the image that's closest to the displayed size.
The MultiRes viewer saves bandwidth by not loading the other versions of the image.
What happened to SPIF?
You can still check out the SPIF image format prototype here. SPIF is problematic because it requires HTTP Range requests to work well. It's also a lot more complicated to parse out images from a single file than it is to have a directory with a separate file for each image size.