I have a slippy map server in-house that can serve tiles a bit faster than going to OSM directly. Is it possible to customize the tile server source in iMatchAnywhere?
IMatch loads the OpenLayers script from the official CDN. I don't provide a server address, that's automatically selected by the OL code.
I have never had a need for this but there is most likely a method in the OL API that allows to configure the map server. You could then use that to customize the C:\ProgramData\photools.com\IMatch6\webroot\imatch\apps\mapapp\ol\olmap.js file to set the map server URL. Keep a copy of the file after your change because it will be overwritten when you update IMatch.
I doubt that such a specialized solution would be useful for other users. But feel free to add a feature request for some 'way' to configure the OSM server in the Map App. See https://gis.stackexchange.com/questions/147882/osm-set-up-openlayers-to-connect-to-local-tileserver for more info.