What are some good signal and image processing blogs worth following?
There are many for different subjects -


Efg's algorithm collection : http://www.efg2.com/Lab/Library/ImageProcessing/index.html
DSP Forum : http://www.dsprelated.com/
Data compression - http://datacompression.info/
About rendering - http://www.realtimerendering.com/portal.html
For all research papers - http://ieeexplore.ieee.org/Xplore/guesthome.jsp
Resources on Mp3 and Audio - http://www.mp3-tech.org/programmer/docs/index.php
Steve on Image Processing - http://blogs.mathworks.com/steve/ 
Image Processing and Retrieval http://savvash.blogspot.com/
Accelerated Image Processing - http://visionexperts.blogspot.com/
The Digital Signal Processing Blog - http://centerk.net/dspblog/
Noise &amp; Vibration Measurement Blog - http://blog.prosig.com/
Image Processing with Matlab, Open Blog - http://imageprocessingblog.com/