If this property is true, then the application will attempt to retrieve the image from the map resource (service) as a binary stream of MIME data. If the resource does not support streaming images but only as image files with a URL, the image will not be retrieved as MIME data but instead use the image URL. In this case the client application must make a subsequent request to the server in order to retrieve this image via the URL.

ArcGIS Server services by default can support either streaming images as MIME data or sending an image-URL response. Manager or ArcCatalog may be used to configure the output options for the map service. The service may be configured to return MIME data only, or MIME data as well as images with URLs. If the service is MIME-only, then the ReturnMimeData property must be true in order for the Map to retrieve images from the service. If the service is MIME plus URL, then ReturnMimeData may be set to either true or false. For more information on configuring and using output directories, see the topic "Creating a server directory" in the ArcGIS Server Help system (at Administering the server - Common administrative tasks). Server Help is installed locally on the server, and is also available online at ESRI Support.

ArcIMS MapResources typically serve maps as images stored temporarily on the server, with the image URL passed to the client to retrieve the image. ArcIMS image (AXL-based) services can be configured to stream data using the <OUTPUT method="stream" /> tag. See the page for the OUTPUT ArcXML tag in the ArcIMS Help (at ArcXML Guide - REQUEST and related elements - Other REQUEST related elements - OUTPUT); this Help is also available online at ESRI Support.

OGC WMS services currently only support returning maps as images with URLs. The ReturnMimeData setting has no effect on how images are retrieved from these services.

Retrieving map images via URL may be complicated when a firewall is placed between the map server and the client application. The client may have difficulty retrieving the image from the map server behind the firewall. In this case retrieving maps as MIME data may be a better option.

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