Errors that are multiplicative with the true visibilities will result in a convolution in the image plane, and thus appear to be "attached" to sources in the image

Gain calibration errors are multiplicative with the visibilities containing baselines to a given antenna

Antenna based gain errors have a sidelobe pattern ranging from a "Y" for short duration errors on the VLA to ring-like structures or ripples for long-duration errors

Atmospheric and Ionospheric errors tend to produce antenna based amplitude and phase differences which (because they are closing) can produce position shifts and image smearing

uv coverage effects are more properly thought of as a spatial filtering of the true sky brightness producing the dirty image

Since the uv sampling function is multiplicative with the true uv distribution, the result is a sidelobe pattern or dirty beam that is convolved with the true image