The file extension JPM marks a bitmap image in the extended JPEG 2000 format. There are several enhancements of the JPEG 200 standard, which open up additional possibilities. The support for the extensions is not yet widespread and does not have to be complete for a program.
The extension JPM identifies files that contain composite JPEG 2000 images. These consist of several levels that have been coded with different methods or emphases in the presentation. In addition, the files include a mechanism for composing the images and metadata.
JPEG 2000 is a digital image compression technique that provides both lossless and lossy compression. It has some advantages over JPEG. Image quality is better at high compression rates and some limitations no longer exist. Eg image size, color depths or support for alpha channels (for transparency). However, this is offset by the licensing-related situation and a significantly higher demand for computing power.
Some programs require a plugin to support the format.