The Blur plug-in blurs an object with an image texture and/or a material on it. Values can be animated. You also have a blur plug-in directly on the image editor, but that only works on one image, using the shader all images within a group can be blurred.
The samples above depict the same image with blur quality set to Low, Normal and High with a range of 100.0. The last is the original (reference) with no blur filter.
Note: This plug-in is located in: Plugins -> Shader -> Filter
Quality: Sets the quality of the blur filter. Low is more pixelated, whereas high is smooth. Available options are Low, Normal and High.
Range: Sets the range of the blur. Range is from 0.0 to 100.0.