Update README.md

Updated Knee Clipper screenshot and thumbnail to reflect latest changes

README.md

@@ -28,7 +28,7 @@ _See the source files for details and instructions._
 | <a name="hard-clipper"></a>[![hard_clipper](https://user-images.githubusercontent.com/53377392/93859333-cefe1d00-fcbd-11ea-82c1-9239de78b162.jpg)](https://user-images.githubusercontent.com/53377392/93859429-e89f6480-fcbd-11ea-9d21-6f378410dcd7.png) | [Hard Clipper](https://github.com/chkhld/jsfx/blob/master/plugins/hard_clipper.jsfx) | Simple and effective, chops away peaks above an adjustable ceiling volume, call it cold transistor distortion if you must. |
 | <a name="impulse-generator"></a>[![impulse_generator](https://user-images.githubusercontent.com/53377392/93859334-cf96b380-fcbd-11ea-82b9-51c37f16f42f.jpg)](https://user-images.githubusercontent.com/53377392/93859431-e89f6480-fcbd-11ea-9455-53d91c143f03.png) | [Impulse Generator](https://github.com/chkhld/jsfx/blob/master/plugins/impulse_generator.jsfx) | Generates a 1-sample impulse when triggered, for use when sampling devices to IRs. |
 | <a name="interpolated-noise"></a>[![interpolated_noise](https://user-images.githubusercontent.com/53377392/93859336-cf96b380-fcbd-11ea-9b8e-24a5dfb002be.jpg)](https://user-images.githubusercontent.com/53377392/93859432-e937fb00-fcbd-11ea-8389-fd8ca945ee03.png) | [Interpolated Noise](https://github.com/chkhld/jsfx/blob/master/plugins/interpolated_noise.jsfx) | Various flavours of pleasingly natural and organically chaotic noise created with the help of various interpolation methods. |
-| <a name="knee-clipper"></a>[![knee_clipper](https://user-images.githubusercontent.com/53377392/120404819-79e3d200-c347-11eb-8220-3c66f7a1c623.jpg)](https://user-images.githubusercontent.com/53377392/120404886-a3046280-c347-11eb-9300-e7969260f4a5.png) | [Knee Clipper](https://github.com/chkhld/jsfx/blob/master/plugins/knee_clipper.jsfx) | A clipper neither purely hard nor purely soft, and yet a unification of both. |
+| <a name="knee-clipper"></a>[![knee_clipper](https://user-images.githubusercontent.com/53377392/120909375-c6dfe500-c674-11eb-862f-dd368627184c.jpg)](https://user-images.githubusercontent.com/53377392/120909370-b6c80580-c674-11eb-81d1-d455e339cf0b.png) | [Knee Clipper](https://github.com/chkhld/jsfx/blob/master/plugins/knee_clipper.jsfx) | A clipper neither purely hard nor purely soft, and yet a unification of both. |
 | <a name="mic-combiner"></a>[![mic_combiner](https://user-images.githubusercontent.com/53377392/95539501-d24c1500-09ee-11eb-92cd-b9a909844730.jpg)](https://user-images.githubusercontent.com/53377392/95539495-ceb88e00-09ee-11eb-9ad3-cb49120c1ce3.png) | [Mic Combiner](https://github.com/chkhld/jsfx/blob/master/plugins/mic_combiner.jsfx) | Utility to facilitate the process of merging two mono microphone signals into one. Processes each microphone signal individually, allows to set a balance/mix between both microphones, and sums them to mono. Can adjust timing between signals. |
 | <a name="m-s-fader"></a>[![m-s_fader](https://user-images.githubusercontent.com/53377392/93859337-d02f4a00-fcbd-11ea-9455-9bb28fdfc63e.jpg)](https://user-images.githubusercontent.com/53377392/93859434-e937fb00-fcbd-11ea-81e5-b51d3218eab1.png) | [M-S Fader](https://github.com/chkhld/jsfx/blob/master/plugins/m-s_fader.jsfx) | Converts a stereo source to a Mid/Side signal and then fades between 100% Mid and 100% Side signal, or a mix of both. Great to remove the center signal, or to focus in on it. |
 | <a name="phase-scope"></a>[![phase_scope](https://user-images.githubusercontent.com/53377392/93859338-d02f4a00-fcbd-11ea-8eb7-362d9b0df257.jpg)](https://user-images.githubusercontent.com/53377392/93859438-e9d09180-fcbd-11ea-8515-8df9d63c0fe0.png) | [Phase Scope](https://github.com/chkhld/jsfx/blob/master/plugins/phase_scope.jsfx) | Visualizes the stereo field of a signal, also commonly known as Goniometer, Vector Scope or Lissajous. Selectable visualization colour and optional freeze-on-pause function. |