Snohomish County - Color Orthophotography
These images are in NAD83 Washington State Plane North in feet and were generously provided by the USGS. Each photo is a GEOTiff that decompresses to approximately 100 megabytes in size.
An index map in polygon shapefile format is available here. The IMAGENAME attribute in this shapefile can be used to determine the filename you need if you have difficulty with these web based index maps.
Click an area for more detail: