Filter file selection from file manager via Javascript

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I'm able to open the file manager via javascript and select a file. How do I filter the files so that only JPGs and PNGs will be shown?

Here's the code I'm using to select files (this allows me to select any file type from the file manager).

...
ccm_chooseAsset = addFile; //addFile is my callback
ccm_alLaunchSelectorFileManager('ccm-b-image');
...