swfextract source.swf 

# Objects in file foo.swf:
#  [-i] 14 Shapes: ID(s) 2, 4, 20, 23, 59, 61, 63, 69, 72, 76, 79, 84, 87, 91
#  [-i] 17 MovieClips: ID(s) 5, 6, 15, 21, 25, 49, 55-57, 64, 65, 71, 78, 86, 93, 99, 103
#  [-j] 11 JPEGs: ID(s) 1, 3, 19, 22, 58, 62, 68, 75, 83, 90, 106
#  [-p] 1 PNG: ID(s) 60
# [-f] 1 Frame: ID(s) 0


swfextract -p 60 source.swf -o extracted.png
swfextract -j 106 source.swf -o extracted.jpg
ls

# source.swf
# extracted.png
# extracted.jpg

http://www.swftools.org/swfextract.html

Examples borrowed from http://ubuntuforums.org/showthread.php?t=966877 (comment 3)

Extract/export graphics from Flash *.swf file

flash, web

Bash