http://www.raben.com/maps
http://www.solarmonitor.org/
http://www.solar.ifa.hawaii.edu/ARMaps/today.html
are 3 that use. I used to use the NOAA page (which is the last one) but occasionally they have a holiday and stop posting, so I had to fine the others.
Search for "Active solar region maps", I'm sure you'll find plenty of others as well. They also help to orient your images
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Al.