changing resolution of raster layers

Can anyone tell me if it is possible to change the resolution that a
raster layer is displayed at.

I would appreciate any advice.

Thanks in advance

Paddy

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Patricia (Paddy) Woodman Telephone (0734) 875123 ext 7310
Department of Archaeology Fax (0734) 318132
University of Reading Email larwodmn@reading.ac.uk
Whiteknights
PO Box 218
Reading RG6 2AA