You have a raster layer with pan sharpening being performed at draw time. Raster layers that have already been pan sharpened and saved as a dataset will result in better drawing performance than deriving pan sharpening on the fly.
Solutions
Check the drawing performance for your layer or basemap layer in ArcMap. If you are publishing, check the drawing performance for your service in the Preview window.
If you want to improve performance, turn off pan sharpening, precompute this as a property of a raster dataset for display purposes, then rebuild your map layer to use the new pan-sharpened raster. See Creating a Pan-Sharpened Raster Dataset for more information.
Alternatively, use ArcGIS Image Server to serve pan-sharpened rasters directly into your map as a web service. You would replace your raster layer with a new image service layer. For thoughts on how to implement this approach, read the More Information section below.
More information
ArcGIS provides a series of tools for improving the display of imagery, including pan sharpening. Panchromatic sharpening fuses a higher-resolution panchromatic image (or raster band) with a lower-resolution multiband raster dataset. This produces a multiband raster dataset with the resolution of the panchromatic raster where the two rasters fully overlap.
You can use either of the following two approaches to apply this pan sharpening:
You can precompute the pan-sharpened raster and save a new raster dataset for high-performance display. See About panchromatic sharpening for more information.
Alternatively, you can derive a pan-sharpened portrayal of your raster data on the fly as the map is displayed. If ArcMap is used for this task (by setting the raster layer's display properties to use pan sharpening), this will potentially degrade drawing performance of a dynamic map because of the computation time involved. However, you can use ArcGIS Image Server to dynamically compute and serve your raster data using pan sharpening (and other image processing techniques such as orthorectification) to get fast, scalable performance.
Your map design will need to change to use ArcGIS Image Server. You would remove image layers from your ArcMap document. In your web application, you would mash up your resulting map service with the image service. An ArcGIS Image Service combined with a map serviceSee About adding an image service layer to ArcMap for more information.
