# Introduction

Media Server can encode images to disk.

There are several reasons you might want to do this:

- To use the images in a front-end application. For example, if you deploy Media Server for broadcast monitoring purposes, you might extract keyframes from the ingested video and use these as thumbnails in a web application that presents the analysis results.
- To obtain training images. For example, if you run face detection on a video, you can write an image of each detected face to disk. You could then use these images for training face recognition.

You can encode images in one of several formats. If you intend to use the images for training, Micro Focus recommends using a format that is not compressed, or uses lossless compression. PNG is a good choice for training images. The JPEG image format uses lossy compression to reduce file size and, as a result, the quality of the image is reduced. This makes JPEG images unsuitable for training but the smaller file size is advantageous if you intend to use the images in a front-end that might be viewed over the web.

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