```release-note
We create a new config option MaxImageDecoderConcurrency which
indicates how many images can be decoded concurrently at once.
The default is -1 which means number of CPUs present.
This affects the total memory consumption of the server. The
maximum memory of a single image is dictated by MaxImageResolution * 24 bytes.
Therefore, a good rule of thumb to follow is that MaxImageResolution
* MaxImageDecoderConcurrency * 24 should be less then the allocated memory for
image decoding.
```
https://mattermost.atlassian.net/browse/MM-43733
7c1b8cd937