What are the consequences of setting the SupportedImageReturnTypes to MIME in ArcGIS

Discussion created by dev3is on Feb 22, 2011
Latest reply on Jun 9, 2011 by zjankovskyarcdata-cz-esridist
I am currently exploring using the ExportMap function on the rest endpoint of a Cached Map Service.( I want to export only some layer within a Mapservice).

I have found that if you change the SupportedImageReturnTypes to MIME of a mxd based mapservice, you can export sublayers of a cached mapservice. (As an aside, you can't do this, if it is a msd based mapservice; even if you change SupportedImageReturnTypes from MIME+url to MIME, the exported image has all the layers. I think it directly returns the cached image.)

The ArcGIS Server help mentions that this setting

    ...Specifies whether images will be returned as MIME data or written to disk (MIME + URL). If you choose URL, you must have a server directory specified for the configuration.

I have tested this out and saw that if the setting was set to MIME+url, then a single temp png file is created in the output director, but it changes as the user pans the map & is deleted within a few seconds.

This is different from the cache, which remains on disk.

I am wondering if it is a good idea to set the setting to MIME, or would it have some consequence on performance.

Does anyone have any experience with this setting?